ETH Price: $3,040.94 (+1.93%)

Transaction Decoder

Block:
24124239 at Dec-30-2025 08:24:23 AM +UTC
Transaction Fee:
0.00006619147778852 ETH $0.20
Gas Used:
451,780 Gas / 0.146512634 Gwei

Emitted Events:

89 0x4aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9.0x19e781916118c373dadcb7776fae0a2dbb6bbdeedae143ce68031e22801ef865( 0x19e781916118c373dadcb7776fae0a2dbb6bbdeedae143ce68031e22801ef865, cdc090d8595e1835ca970cac20abe5240c5ebb5674094a3ff46e54e993994547 )
90 EntryPoint.Deposited( account=0x4aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9, totalDeposit=187361566512780 )
91 EntryPoint.BeforeExecution( )
92 FiatTokenProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x0000000000000000000000004aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9, 0x0000000000000000000000004afff4cbbbda5351ae39b0bef7d851a37189cd2b, 00000000000000000000000000000000000000000000000000000000907b4e00 )
93 EntryPoint.UserOperationEvent( userOpHash=CDC090D8595E1835CA970CAC20ABE5240C5EBB5674094A3FF46E54E993994547, sender=0x4aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9, paymaster=0x00000000...000000000, nonce=119, success=True, actualGasCost=63370177852293, actualGasUsed=501111 )

Account State Difference:

  Address   Before After State Difference Code
(quasarbuilder)
12.680698423644406516 Eth12.680722392051178896 Eth0.00002396840677238
0x4337013e...FD37BBeb1
(Pimlico: ERC-4337 Bundler 13)
0.252455752577845376 Eth
Nonce: 16327
0.252452931277909149 Eth
Nonce: 16328
0.000002821299936227
0x4aAf5205...F5C7eA8E9 0.052760806758313122 Eth0.052629258990655334 Eth0.000131547767657788
0x5FF137D4...a026d2789
(Entry Point 0.6.0)
311.664291865109324288 Eth311.664360042699129783 Eth0.000068177589805495
0xA0b86991...E3606eB48

Execution Trace

EntryPoint.handleOps( ops=, beneficiary=0x4337013eF5Cd421ceF649fC58c1B0DEFD37BBeb1 )
  • 0x4aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9.3a871cdd( )
    • 0x2e7f1dae1f3799d20f5c31befdc7a620f664728d.cdffacc6( )
    • 0xfde53272dcd7938d16e031a6989753c321728332.3a871cdd( )
      • 0xee1af8e967ec04c84711842796a5e714d2fd33e6.8dd50121( )
        • Null: 0x000...002.7b227479( )
        • Null: 0x000...002.1a70842a( )
        • Null: 0x000...005.00000000( )
        • Null: 0x000...005.00000000( )
        • ETH 0.000131547767657788 EntryPoint.CALL( )
        • EntryPoint.innerHandleOp( callData=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opInfo=[{name:mUserOp, type:tuple, order:1, indexed:false, value:[{name:sender, type:address, order:1, indexed:false, value:0x4aAf5205E2e96b6CE1B13ECcB5fa925F5C7eA8E9, valueString:0x4aAf5205E2e96b6CE1B13ECcB5fa925F5C7eA8E9}, {name:nonce, type:uint256, order:2, indexed:false, value:119, valueString:119}, {name:callGasLimit, type:uint256, order:3, indexed:false, value:171753, valueString:171753}, {name:verificationGasLimit, type:uint256, order:4, indexed:false, value:686798, valueString:686798}, {name:preVerificationGas, type:uint256, order:5, indexed:false, value:99334, valueString:99334}, {name:paymaster, type:address, order:6, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:maxFeePerGas, type:uint256, order:7, indexed:false, value:195599228, valueString:195599228}, {name:maxPriorityFeePerGas, type:uint256, order:8, indexed:false, value:33000000, valueString:33000000}], valueString:[{name:sender, type:address, order:1, indexed:false, value:0x4aAf5205E2e96b6CE1B13ECcB5fa925F5C7eA8E9, valueString:0x4aAf5205E2e96b6CE1B13ECcB5fa925F5C7eA8E9}, {name:nonce, type:uint256, order:2, indexed:false, value:119, valueString:119}, {name:callGasLimit, type:uint256, order:3, indexed:false, value:171753, valueString:171753}, {name:verificationGasLimit, type:uint256, order:4, indexed:false, value:686798, valueString:686798}, {name:preVerificationGas, type:uint256, order:5, indexed:false, value:99334, valueString:99334}, {name:paymaster, type:address, order:6, indexed:false, value:0x0000000000000000000000000000000000000000, valueString:0x0000000000000000000000000000000000000000}, {name:maxFeePerGas, type:uint256, order:7, indexed:false, value:195599228, valueString:195599228}, {name:maxPriorityFeePerGas, type:uint256, order:8, indexed:false, value:33000000, valueString:33000000}]}, {name:userOpHash, type:bytes32, order:2, indexed:false, value:CDC090D8595E1835CA970CAC20ABE5240C5EBB5674094A3FF46E54E993994547, valueString:CDC090D8595E1835CA970CAC20ABE5240C5EBB5674094A3FF46E54E993994547}, {name:prefund, type:uint256, order:3, indexed:false, value:187361566512780, valueString:187361566512780}, {name:contextOffset, type:uint256, order:4, indexed:false, value:96, valueString:96}, {name:preOpGas, type:uint256, order:5, indexed:false, value:461869, valueString:461869}], context=0x ) => ( actualGasCost=63370177852293 )
          • 0x4aaf5205e2e96b6ce1b13eccb5fa925f5c7ea8e9.47e1da2a( )
            • 0x2e7f1dae1f3799d20f5c31befdc7a620f664728d.cdffacc6( )
            • 0xfde53272dcd7938d16e031a6989753c321728332.47e1da2a( )
              • FiatTokenProxy.a9059cbb( )
                • FiatTokenV2_2.transfer( to=0x4AFFF4CbBbdA5351AE39B0bEf7D851A37189cD2B, value=2424000000 ) => ( True )
                • ETH 0.000063370177852293 Pimlico: ERC-4337 Bundler 13.CALL( )
                  handleOps[EntryPoint (ln:137)]
                  File 1 of 3: EntryPoint
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)
                  pragma solidity ^0.8.0;
                  /**
                   * @dev Contract module that helps prevent reentrant calls to a function.
                   *
                   * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
                   * available, which can be applied to functions to make sure there are no nested
                   * (reentrant) calls to them.
                   *
                   * Note that because there is a single `nonReentrant` guard, functions marked as
                   * `nonReentrant` may not call one another. This can be worked around by making
                   * those functions `private`, and then adding `external` `nonReentrant` entry
                   * points to them.
                   *
                   * TIP: If you would like to learn more about reentrancy and alternative ways
                   * to protect against it, check out our blog post
                   * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
                   */
                  abstract contract ReentrancyGuard {
                      // Booleans are more expensive than uint256 or any type that takes up a full
                      // word because each write operation emits an extra SLOAD to first read the
                      // slot's contents, replace the bits taken up by the boolean, and then write
                      // back. This is the compiler's defense against contract upgrades and
                      // pointer aliasing, and it cannot be disabled.
                      // The values being non-zero value makes deployment a bit more expensive,
                      // but in exchange the refund on every call to nonReentrant will be lower in
                      // amount. Since refunds are capped to a percentage of the total
                      // transaction's gas, it is best to keep them low in cases like this one, to
                      // increase the likelihood of the full refund coming into effect.
                      uint256 private constant _NOT_ENTERED = 1;
                      uint256 private constant _ENTERED = 2;
                      uint256 private _status;
                      constructor() {
                          _status = _NOT_ENTERED;
                      }
                      /**
                       * @dev Prevents a contract from calling itself, directly or indirectly.
                       * Calling a `nonReentrant` function from another `nonReentrant`
                       * function is not supported. It is possible to prevent this from happening
                       * by making the `nonReentrant` function external, and making it call a
                       * `private` function that does the actual work.
                       */
                      modifier nonReentrant() {
                          _nonReentrantBefore();
                          _;
                          _nonReentrantAfter();
                      }
                      function _nonReentrantBefore() private {
                          // On the first call to nonReentrant, _status will be _NOT_ENTERED
                          require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
                          // Any calls to nonReentrant after this point will fail
                          _status = _ENTERED;
                      }
                      function _nonReentrantAfter() private {
                          // By storing the original value once again, a refund is triggered (see
                          // https://eips.ethereum.org/EIPS/eip-2200)
                          _status = _NOT_ENTERED;
                      }
                  }
                  /**
                   ** Account-Abstraction (EIP-4337) singleton EntryPoint implementation.
                   ** Only one instance required on each chain.
                   **/
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  /* solhint-disable avoid-low-level-calls */
                  /* solhint-disable no-inline-assembly */
                  import "../interfaces/IAccount.sol";
                  import "../interfaces/IPaymaster.sol";
                  import "../interfaces/IEntryPoint.sol";
                  import "../utils/Exec.sol";
                  import "./StakeManager.sol";
                  import "./SenderCreator.sol";
                  import "./Helpers.sol";
                  import "./NonceManager.sol";
                  import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
                  contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard {
                      using UserOperationLib for UserOperation;
                      SenderCreator private immutable senderCreator = new SenderCreator();
                      // internal value used during simulation: need to query aggregator.
                      address private constant SIMULATE_FIND_AGGREGATOR = address(1);
                      // marker for inner call revert on out of gas
                      bytes32 private constant INNER_OUT_OF_GAS = hex'deaddead';
                      uint256 private constant REVERT_REASON_MAX_LEN = 2048;
                      /**
                       * for simulation purposes, validateUserOp (and validatePaymasterUserOp) must return this value
                       * in case of signature failure, instead of revert.
                       */
                      uint256 public constant SIG_VALIDATION_FAILED = 1;
                      /**
                       * compensate the caller's beneficiary address with the collected fees of all UserOperations.
                       * @param beneficiary the address to receive the fees
                       * @param amount amount to transfer.
                       */
                      function _compensate(address payable beneficiary, uint256 amount) internal {
                          require(beneficiary != address(0), "AA90 invalid beneficiary");
                          (bool success,) = beneficiary.call{value : amount}("");
                          require(success, "AA91 failed send to beneficiary");
                      }
                      /**
                       * execute a user op
                       * @param opIndex index into the opInfo array
                       * @param userOp the userOp to execute
                       * @param opInfo the opInfo filled by validatePrepayment for this userOp.
                       * @return collected the total amount this userOp paid.
                       */
                      function _executeUserOp(uint256 opIndex, UserOperation calldata userOp, UserOpInfo memory opInfo) private returns (uint256 collected) {
                          uint256 preGas = gasleft();
                          bytes memory context = getMemoryBytesFromOffset(opInfo.contextOffset);
                          try this.innerHandleOp(userOp.callData, opInfo, context) returns (uint256 _actualGasCost) {
                              collected = _actualGasCost;
                          } catch {
                              bytes32 innerRevertCode;
                              assembly {
                                  returndatacopy(0, 0, 32)
                                  innerRevertCode := mload(0)
                              }
                              // handleOps was called with gas limit too low. abort entire bundle.
                              if (innerRevertCode == INNER_OUT_OF_GAS) {
                                  //report paymaster, since if it is not deliberately caused by the bundler,
                                  // it must be a revert caused by paymaster.
                                  revert FailedOp(opIndex, "AA95 out of gas");
                              }
                              uint256 actualGas = preGas - gasleft() + opInfo.preOpGas;
                              collected = _handlePostOp(opIndex, IPaymaster.PostOpMode.postOpReverted, opInfo, context, actualGas);
                          }
                      }
                      /**
                       * Execute a batch of UserOperations.
                       * no signature aggregator is used.
                       * if any account requires an aggregator (that is, it returned an aggregator when
                       * performing simulateValidation), then handleAggregatedOps() must be used instead.
                       * @param ops the operations to execute
                       * @param beneficiary the address to receive the fees
                       */
                      function handleOps(UserOperation[] calldata ops, address payable beneficiary) public nonReentrant {
                          uint256 opslen = ops.length;
                          UserOpInfo[] memory opInfos = new UserOpInfo[](opslen);
                      unchecked {
                          for (uint256 i = 0; i < opslen; i++) {
                              UserOpInfo memory opInfo = opInfos[i];
                              (uint256 validationData, uint256 pmValidationData) = _validatePrepayment(i, ops[i], opInfo);
                              _validateAccountAndPaymasterValidationData(i, validationData, pmValidationData, address(0));
                          }
                          uint256 collected = 0;
                          emit BeforeExecution();
                          for (uint256 i = 0; i < opslen; i++) {
                              collected += _executeUserOp(i, ops[i], opInfos[i]);
                          }
                          _compensate(beneficiary, collected);
                      } //unchecked
                      }
                      /**
                       * Execute a batch of UserOperation with Aggregators
                       * @param opsPerAggregator the operations to execute, grouped by aggregator (or address(0) for no-aggregator accounts)
                       * @param beneficiary the address to receive the fees
                       */
                      function handleAggregatedOps(
                          UserOpsPerAggregator[] calldata opsPerAggregator,
                          address payable beneficiary
                      ) public nonReentrant {
                          uint256 opasLen = opsPerAggregator.length;
                          uint256 totalOps = 0;
                          for (uint256 i = 0; i < opasLen; i++) {
                              UserOpsPerAggregator calldata opa = opsPerAggregator[i];
                              UserOperation[] calldata ops = opa.userOps;
                              IAggregator aggregator = opa.aggregator;
                              //address(1) is special marker of "signature error"
                              require(address(aggregator) != address(1), "AA96 invalid aggregator");
                              if (address(aggregator) != address(0)) {
                                  // solhint-disable-next-line no-empty-blocks
                                  try aggregator.validateSignatures(ops, opa.signature) {}
                                  catch {
                                      revert SignatureValidationFailed(address(aggregator));
                                  }
                              }
                              totalOps += ops.length;
                          }
                          UserOpInfo[] memory opInfos = new UserOpInfo[](totalOps);
                          emit BeforeExecution();
                          uint256 opIndex = 0;
                          for (uint256 a = 0; a < opasLen; a++) {
                              UserOpsPerAggregator calldata opa = opsPerAggregator[a];
                              UserOperation[] calldata ops = opa.userOps;
                              IAggregator aggregator = opa.aggregator;
                              uint256 opslen = ops.length;
                              for (uint256 i = 0; i < opslen; i++) {
                                  UserOpInfo memory opInfo = opInfos[opIndex];
                                  (uint256 validationData, uint256 paymasterValidationData) = _validatePrepayment(opIndex, ops[i], opInfo);
                                  _validateAccountAndPaymasterValidationData(i, validationData, paymasterValidationData, address(aggregator));
                                  opIndex++;
                              }
                          }
                          uint256 collected = 0;
                          opIndex = 0;
                          for (uint256 a = 0; a < opasLen; a++) {
                              UserOpsPerAggregator calldata opa = opsPerAggregator[a];
                              emit SignatureAggregatorChanged(address(opa.aggregator));
                              UserOperation[] calldata ops = opa.userOps;
                              uint256 opslen = ops.length;
                              for (uint256 i = 0; i < opslen; i++) {
                                  collected += _executeUserOp(opIndex, ops[i], opInfos[opIndex]);
                                  opIndex++;
                              }
                          }
                          emit SignatureAggregatorChanged(address(0));
                          _compensate(beneficiary, collected);
                      }
                      /// @inheritdoc IEntryPoint
                      function simulateHandleOp(UserOperation calldata op, address target, bytes calldata targetCallData) external override {
                          UserOpInfo memory opInfo;
                          _simulationOnlyValidations(op);
                          (uint256 validationData, uint256 paymasterValidationData) = _validatePrepayment(0, op, opInfo);
                          ValidationData memory data = _intersectTimeRange(validationData, paymasterValidationData);
                          numberMarker();
                          uint256 paid = _executeUserOp(0, op, opInfo);
                          numberMarker();
                          bool targetSuccess;
                          bytes memory targetResult;
                          if (target != address(0)) {
                              (targetSuccess, targetResult) = target.call(targetCallData);
                          }
                          revert ExecutionResult(opInfo.preOpGas, paid, data.validAfter, data.validUntil, targetSuccess, targetResult);
                      }
                      // A memory copy of UserOp static fields only.
                      // Excluding: callData, initCode and signature. Replacing paymasterAndData with paymaster.
                      struct MemoryUserOp {
                          address sender;
                          uint256 nonce;
                          uint256 callGasLimit;
                          uint256 verificationGasLimit;
                          uint256 preVerificationGas;
                          address paymaster;
                          uint256 maxFeePerGas;
                          uint256 maxPriorityFeePerGas;
                      }
                      struct UserOpInfo {
                          MemoryUserOp mUserOp;
                          bytes32 userOpHash;
                          uint256 prefund;
                          uint256 contextOffset;
                          uint256 preOpGas;
                      }
                      /**
                       * inner function to handle a UserOperation.
                       * Must be declared "external" to open a call context, but it can only be called by handleOps.
                       */
                      function innerHandleOp(bytes memory callData, UserOpInfo memory opInfo, bytes calldata context) external returns (uint256 actualGasCost) {
                          uint256 preGas = gasleft();
                          require(msg.sender == address(this), "AA92 internal call only");
                          MemoryUserOp memory mUserOp = opInfo.mUserOp;
                          uint callGasLimit = mUserOp.callGasLimit;
                      unchecked {
                          // handleOps was called with gas limit too low. abort entire bundle.
                          if (gasleft() < callGasLimit + mUserOp.verificationGasLimit + 5000) {
                              assembly {
                                  mstore(0, INNER_OUT_OF_GAS)
                                  revert(0, 32)
                              }
                          }
                      }
                          IPaymaster.PostOpMode mode = IPaymaster.PostOpMode.opSucceeded;
                          if (callData.length > 0) {
                              bool success = Exec.call(mUserOp.sender, 0, callData, callGasLimit);
                              if (!success) {
                                  bytes memory result = Exec.getReturnData(REVERT_REASON_MAX_LEN);
                                  if (result.length > 0) {
                                      emit UserOperationRevertReason(opInfo.userOpHash, mUserOp.sender, mUserOp.nonce, result);
                                  }
                                  mode = IPaymaster.PostOpMode.opReverted;
                              }
                          }
                      unchecked {
                          uint256 actualGas = preGas - gasleft() + opInfo.preOpGas;
                          //note: opIndex is ignored (relevant only if mode==postOpReverted, which is only possible outside of innerHandleOp)
                          return _handlePostOp(0, mode, opInfo, context, actualGas);
                      }
                      }
                      /**
                       * generate a request Id - unique identifier for this request.
                       * the request ID is a hash over the content of the userOp (except the signature), the entrypoint and the chainid.
                       */
                      function getUserOpHash(UserOperation calldata userOp) public view returns (bytes32) {
                          return keccak256(abi.encode(userOp.hash(), address(this), block.chainid));
                      }
                      /**
                       * copy general fields from userOp into the memory opInfo structure.
                       */
                      function _copyUserOpToMemory(UserOperation calldata userOp, MemoryUserOp memory mUserOp) internal pure {
                          mUserOp.sender = userOp.sender;
                          mUserOp.nonce = userOp.nonce;
                          mUserOp.callGasLimit = userOp.callGasLimit;
                          mUserOp.verificationGasLimit = userOp.verificationGasLimit;
                          mUserOp.preVerificationGas = userOp.preVerificationGas;
                          mUserOp.maxFeePerGas = userOp.maxFeePerGas;
                          mUserOp.maxPriorityFeePerGas = userOp.maxPriorityFeePerGas;
                          bytes calldata paymasterAndData = userOp.paymasterAndData;
                          if (paymasterAndData.length > 0) {
                              require(paymasterAndData.length >= 20, "AA93 invalid paymasterAndData");
                              mUserOp.paymaster = address(bytes20(paymasterAndData[: 20]));
                          } else {
                              mUserOp.paymaster = address(0);
                          }
                      }
                      /**
                       * Simulate a call to account.validateUserOp and paymaster.validatePaymasterUserOp.
                       * @dev this method always revert. Successful result is ValidationResult error. other errors are failures.
                       * @dev The node must also verify it doesn't use banned opcodes, and that it doesn't reference storage outside the account's data.
                       * @param userOp the user operation to validate.
                       */
                      function simulateValidation(UserOperation calldata userOp) external {
                          UserOpInfo memory outOpInfo;
                          _simulationOnlyValidations(userOp);
                          (uint256 validationData, uint256 paymasterValidationData) = _validatePrepayment(0, userOp, outOpInfo);
                          StakeInfo memory paymasterInfo = _getStakeInfo(outOpInfo.mUserOp.paymaster);
                          StakeInfo memory senderInfo = _getStakeInfo(outOpInfo.mUserOp.sender);
                          StakeInfo memory factoryInfo;
                          {
                              bytes calldata initCode = userOp.initCode;
                              address factory = initCode.length >= 20 ? address(bytes20(initCode[0 : 20])) : address(0);
                              factoryInfo = _getStakeInfo(factory);
                          }
                          ValidationData memory data = _intersectTimeRange(validationData, paymasterValidationData);
                          address aggregator = data.aggregator;
                          bool sigFailed = aggregator == address(1);
                          ReturnInfo memory returnInfo = ReturnInfo(outOpInfo.preOpGas, outOpInfo.prefund,
                              sigFailed, data.validAfter, data.validUntil, getMemoryBytesFromOffset(outOpInfo.contextOffset));
                          if (aggregator != address(0) && aggregator != address(1)) {
                              AggregatorStakeInfo memory aggregatorInfo = AggregatorStakeInfo(aggregator, _getStakeInfo(aggregator));
                              revert ValidationResultWithAggregation(returnInfo, senderInfo, factoryInfo, paymasterInfo, aggregatorInfo);
                          }
                          revert ValidationResult(returnInfo, senderInfo, factoryInfo, paymasterInfo);
                      }
                      function _getRequiredPrefund(MemoryUserOp memory mUserOp) internal pure returns (uint256 requiredPrefund) {
                      unchecked {
                          //when using a Paymaster, the verificationGasLimit is used also to as a limit for the postOp call.
                          // our security model might call postOp eventually twice
                          uint256 mul = mUserOp.paymaster != address(0) ? 3 : 1;
                          uint256 requiredGas = mUserOp.callGasLimit + mUserOp.verificationGasLimit * mul + mUserOp.preVerificationGas;
                          requiredPrefund = requiredGas * mUserOp.maxFeePerGas;
                      }
                      }
                      // create the sender's contract if needed.
                      function _createSenderIfNeeded(uint256 opIndex, UserOpInfo memory opInfo, bytes calldata initCode) internal {
                          if (initCode.length != 0) {
                              address sender = opInfo.mUserOp.sender;
                              if (sender.code.length != 0) revert FailedOp(opIndex, "AA10 sender already constructed");
                              address sender1 = senderCreator.createSender{gas : opInfo.mUserOp.verificationGasLimit}(initCode);
                              if (sender1 == address(0)) revert FailedOp(opIndex, "AA13 initCode failed or OOG");
                              if (sender1 != sender) revert FailedOp(opIndex, "AA14 initCode must return sender");
                              if (sender1.code.length == 0) revert FailedOp(opIndex, "AA15 initCode must create sender");
                              address factory = address(bytes20(initCode[0 : 20]));
                              emit AccountDeployed(opInfo.userOpHash, sender, factory, opInfo.mUserOp.paymaster);
                          }
                      }
                      /**
                       * Get counterfactual sender address.
                       *  Calculate the sender contract address that will be generated by the initCode and salt in the UserOperation.
                       * this method always revert, and returns the address in SenderAddressResult error
                       * @param initCode the constructor code to be passed into the UserOperation.
                       */
                      function getSenderAddress(bytes calldata initCode) public {
                          address sender = senderCreator.createSender(initCode);
                          revert SenderAddressResult(sender);
                      }
                      function _simulationOnlyValidations(UserOperation calldata userOp) internal view {
                          // solhint-disable-next-line no-empty-blocks
                          try this._validateSenderAndPaymaster(userOp.initCode, userOp.sender, userOp.paymasterAndData) {}
                          catch Error(string memory revertReason) {
                              if (bytes(revertReason).length != 0) {
                                  revert FailedOp(0, revertReason);
                              }
                          }
                      }
                      /**
                      * Called only during simulation.
                      * This function always reverts to prevent warm/cold storage differentiation in simulation vs execution.
                      */
                      function _validateSenderAndPaymaster(bytes calldata initCode, address sender, bytes calldata paymasterAndData) external view {
                          if (initCode.length == 0 && sender.code.length == 0) {
                              // it would revert anyway. but give a meaningful message
                              revert("AA20 account not deployed");
                          }
                          if (paymasterAndData.length >= 20) {
                              address paymaster = address(bytes20(paymasterAndData[0 : 20]));
                              if (paymaster.code.length == 0) {
                                  // it would revert anyway. but give a meaningful message
                                  revert("AA30 paymaster not deployed");
                              }
                          }
                          // always revert
                          revert("");
                      }
                      /**
                       * call account.validateUserOp.
                       * revert (with FailedOp) in case validateUserOp reverts, or account didn't send required prefund.
                       * decrement account's deposit if needed
                       */
                      function _validateAccountPrepayment(uint256 opIndex, UserOperation calldata op, UserOpInfo memory opInfo, uint256 requiredPrefund)
                      internal returns (uint256 gasUsedByValidateAccountPrepayment, uint256 validationData) {
                      unchecked {
                          uint256 preGas = gasleft();
                          MemoryUserOp memory mUserOp = opInfo.mUserOp;
                          address sender = mUserOp.sender;
                          _createSenderIfNeeded(opIndex, opInfo, op.initCode);
                          address paymaster = mUserOp.paymaster;
                          numberMarker();
                          uint256 missingAccountFunds = 0;
                          if (paymaster == address(0)) {
                              uint256 bal = balanceOf(sender);
                              missingAccountFunds = bal > requiredPrefund ? 0 : requiredPrefund - bal;
                          }
                          try IAccount(sender).validateUserOp{gas : mUserOp.verificationGasLimit}(op, opInfo.userOpHash, missingAccountFunds)
                          returns (uint256 _validationData) {
                              validationData = _validationData;
                          } catch Error(string memory revertReason) {
                              revert FailedOp(opIndex, string.concat("AA23 reverted: ", revertReason));
                          } catch {
                              revert FailedOp(opIndex, "AA23 reverted (or OOG)");
                          }
                          if (paymaster == address(0)) {
                              DepositInfo storage senderInfo = deposits[sender];
                              uint256 deposit = senderInfo.deposit;
                              if (requiredPrefund > deposit) {
                                  revert FailedOp(opIndex, "AA21 didn't pay prefund");
                              }
                              senderInfo.deposit = uint112(deposit - requiredPrefund);
                          }
                          gasUsedByValidateAccountPrepayment = preGas - gasleft();
                      }
                      }
                      /**
                       * In case the request has a paymaster:
                       * Validate paymaster has enough deposit.
                       * Call paymaster.validatePaymasterUserOp.
                       * Revert with proper FailedOp in case paymaster reverts.
                       * Decrement paymaster's deposit
                       */
                      function _validatePaymasterPrepayment(uint256 opIndex, UserOperation calldata op, UserOpInfo memory opInfo, uint256 requiredPreFund, uint256 gasUsedByValidateAccountPrepayment)
                      internal returns (bytes memory context, uint256 validationData) {
                      unchecked {
                          MemoryUserOp memory mUserOp = opInfo.mUserOp;
                          uint256 verificationGasLimit = mUserOp.verificationGasLimit;
                          require(verificationGasLimit > gasUsedByValidateAccountPrepayment, "AA41 too little verificationGas");
                          uint256 gas = verificationGasLimit - gasUsedByValidateAccountPrepayment;
                          address paymaster = mUserOp.paymaster;
                          DepositInfo storage paymasterInfo = deposits[paymaster];
                          uint256 deposit = paymasterInfo.deposit;
                          if (deposit < requiredPreFund) {
                              revert FailedOp(opIndex, "AA31 paymaster deposit too low");
                          }
                          paymasterInfo.deposit = uint112(deposit - requiredPreFund);
                          try IPaymaster(paymaster).validatePaymasterUserOp{gas : gas}(op, opInfo.userOpHash, requiredPreFund) returns (bytes memory _context, uint256 _validationData){
                              context = _context;
                              validationData = _validationData;
                          } catch Error(string memory revertReason) {
                              revert FailedOp(opIndex, string.concat("AA33 reverted: ", revertReason));
                          } catch {
                              revert FailedOp(opIndex, "AA33 reverted (or OOG)");
                          }
                      }
                      }
                      /**
                       * revert if either account validationData or paymaster validationData is expired
                       */
                      function _validateAccountAndPaymasterValidationData(uint256 opIndex, uint256 validationData, uint256 paymasterValidationData, address expectedAggregator) internal view {
                          (address aggregator, bool outOfTimeRange) = _getValidationData(validationData);
                          if (expectedAggregator != aggregator) {
                              revert FailedOp(opIndex, "AA24 signature error");
                          }
                          if (outOfTimeRange) {
                              revert FailedOp(opIndex, "AA22 expired or not due");
                          }
                          //pmAggregator is not a real signature aggregator: we don't have logic to handle it as address.
                          // non-zero address means that the paymaster fails due to some signature check (which is ok only during estimation)
                          address pmAggregator;
                          (pmAggregator, outOfTimeRange) = _getValidationData(paymasterValidationData);
                          if (pmAggregator != address(0)) {
                              revert FailedOp(opIndex, "AA34 signature error");
                          }
                          if (outOfTimeRange) {
                              revert FailedOp(opIndex, "AA32 paymaster expired or not due");
                          }
                      }
                      function _getValidationData(uint256 validationData) internal view returns (address aggregator, bool outOfTimeRange) {
                          if (validationData == 0) {
                              return (address(0), false);
                          }
                          ValidationData memory data = _parseValidationData(validationData);
                          // solhint-disable-next-line not-rely-on-time
                          outOfTimeRange = block.timestamp > data.validUntil || block.timestamp < data.validAfter;
                          aggregator = data.aggregator;
                      }
                      /**
                       * validate account and paymaster (if defined).
                       * also make sure total validation doesn't exceed verificationGasLimit
                       * this method is called off-chain (simulateValidation()) and on-chain (from handleOps)
                       * @param opIndex the index of this userOp into the "opInfos" array
                       * @param userOp the userOp to validate
                       */
                      function _validatePrepayment(uint256 opIndex, UserOperation calldata userOp, UserOpInfo memory outOpInfo)
                      private returns (uint256 validationData, uint256 paymasterValidationData) {
                          uint256 preGas = gasleft();
                          MemoryUserOp memory mUserOp = outOpInfo.mUserOp;
                          _copyUserOpToMemory(userOp, mUserOp);
                          outOpInfo.userOpHash = getUserOpHash(userOp);
                          // validate all numeric values in userOp are well below 128 bit, so they can safely be added
                          // and multiplied without causing overflow
                          uint256 maxGasValues = mUserOp.preVerificationGas | mUserOp.verificationGasLimit | mUserOp.callGasLimit |
                          userOp.maxFeePerGas | userOp.maxPriorityFeePerGas;
                          require(maxGasValues <= type(uint120).max, "AA94 gas values overflow");
                          uint256 gasUsedByValidateAccountPrepayment;
                          (uint256 requiredPreFund) = _getRequiredPrefund(mUserOp);
                          (gasUsedByValidateAccountPrepayment, validationData) = _validateAccountPrepayment(opIndex, userOp, outOpInfo, requiredPreFund);
                          if (!_validateAndUpdateNonce(mUserOp.sender, mUserOp.nonce)) {
                              revert FailedOp(opIndex, "AA25 invalid account nonce");
                          }
                          //a "marker" where account opcode validation is done and paymaster opcode validation is about to start
                          // (used only by off-chain simulateValidation)
                          numberMarker();
                          bytes memory context;
                          if (mUserOp.paymaster != address(0)) {
                              (context, paymasterValidationData) = _validatePaymasterPrepayment(opIndex, userOp, outOpInfo, requiredPreFund, gasUsedByValidateAccountPrepayment);
                          }
                      unchecked {
                          uint256 gasUsed = preGas - gasleft();
                          if (userOp.verificationGasLimit < gasUsed) {
                              revert FailedOp(opIndex, "AA40 over verificationGasLimit");
                          }
                          outOpInfo.prefund = requiredPreFund;
                          outOpInfo.contextOffset = getOffsetOfMemoryBytes(context);
                          outOpInfo.preOpGas = preGas - gasleft() + userOp.preVerificationGas;
                      }
                      }
                      /**
                       * process post-operation.
                       * called just after the callData is executed.
                       * if a paymaster is defined and its validation returned a non-empty context, its postOp is called.
                       * the excess amount is refunded to the account (or paymaster - if it was used in the request)
                       * @param opIndex index in the batch
                       * @param mode - whether is called from innerHandleOp, or outside (postOpReverted)
                       * @param opInfo userOp fields and info collected during validation
                       * @param context the context returned in validatePaymasterUserOp
                       * @param actualGas the gas used so far by this user operation
                       */
                      function _handlePostOp(uint256 opIndex, IPaymaster.PostOpMode mode, UserOpInfo memory opInfo, bytes memory context, uint256 actualGas) private returns (uint256 actualGasCost) {
                          uint256 preGas = gasleft();
                      unchecked {
                          address refundAddress;
                          MemoryUserOp memory mUserOp = opInfo.mUserOp;
                          uint256 gasPrice = getUserOpGasPrice(mUserOp);
                          address paymaster = mUserOp.paymaster;
                          if (paymaster == address(0)) {
                              refundAddress = mUserOp.sender;
                          } else {
                              refundAddress = paymaster;
                              if (context.length > 0) {
                                  actualGasCost = actualGas * gasPrice;
                                  if (mode != IPaymaster.PostOpMode.postOpReverted) {
                                      IPaymaster(paymaster).postOp{gas : mUserOp.verificationGasLimit}(mode, context, actualGasCost);
                                  } else {
                                      // solhint-disable-next-line no-empty-blocks
                                      try IPaymaster(paymaster).postOp{gas : mUserOp.verificationGasLimit}(mode, context, actualGasCost) {}
                                      catch Error(string memory reason) {
                                          revert FailedOp(opIndex, string.concat("AA50 postOp reverted: ", reason));
                                      }
                                      catch {
                                          revert FailedOp(opIndex, "AA50 postOp revert");
                                      }
                                  }
                              }
                          }
                          actualGas += preGas - gasleft();
                          actualGasCost = actualGas * gasPrice;
                          if (opInfo.prefund < actualGasCost) {
                              revert FailedOp(opIndex, "AA51 prefund below actualGasCost");
                          }
                          uint256 refund = opInfo.prefund - actualGasCost;
                          _incrementDeposit(refundAddress, refund);
                          bool success = mode == IPaymaster.PostOpMode.opSucceeded;
                          emit UserOperationEvent(opInfo.userOpHash, mUserOp.sender, mUserOp.paymaster, mUserOp.nonce, success, actualGasCost, actualGas);
                      } // unchecked
                      }
                      /**
                       * the gas price this UserOp agrees to pay.
                       * relayer/block builder might submit the TX with higher priorityFee, but the user should not
                       */
                      function getUserOpGasPrice(MemoryUserOp memory mUserOp) internal view returns (uint256) {
                      unchecked {
                          uint256 maxFeePerGas = mUserOp.maxFeePerGas;
                          uint256 maxPriorityFeePerGas = mUserOp.maxPriorityFeePerGas;
                          if (maxFeePerGas == maxPriorityFeePerGas) {
                              //legacy mode (for networks that don't support basefee opcode)
                              return maxFeePerGas;
                          }
                          return min(maxFeePerGas, maxPriorityFeePerGas + block.basefee);
                      }
                      }
                      function min(uint256 a, uint256 b) internal pure returns (uint256) {
                          return a < b ? a : b;
                      }
                      function getOffsetOfMemoryBytes(bytes memory data) internal pure returns (uint256 offset) {
                          assembly {offset := data}
                      }
                      function getMemoryBytesFromOffset(uint256 offset) internal pure returns (bytes memory data) {
                          assembly {data := offset}
                      }
                      //place the NUMBER opcode in the code.
                      // this is used as a marker during simulation, as this OP is completely banned from the simulated code of the
                      // account and paymaster.
                      function numberMarker() internal view {
                          assembly {mstore(0, number())}
                      }
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  /* solhint-disable no-inline-assembly */
                  /**
                   * returned data from validateUserOp.
                   * validateUserOp returns a uint256, with is created by `_packedValidationData` and parsed by `_parseValidationData`
                   * @param aggregator - address(0) - the account validated the signature by itself.
                   *              address(1) - the account failed to validate the signature.
                   *              otherwise - this is an address of a signature aggregator that must be used to validate the signature.
                   * @param validAfter - this UserOp is valid only after this timestamp.
                   * @param validaUntil - this UserOp is valid only up to this timestamp.
                   */
                      struct ValidationData {
                          address aggregator;
                          uint48 validAfter;
                          uint48 validUntil;
                      }
                  //extract sigFailed, validAfter, validUntil.
                  // also convert zero validUntil to type(uint48).max
                      function _parseValidationData(uint validationData) pure returns (ValidationData memory data) {
                          address aggregator = address(uint160(validationData));
                          uint48 validUntil = uint48(validationData >> 160);
                          if (validUntil == 0) {
                              validUntil = type(uint48).max;
                          }
                          uint48 validAfter = uint48(validationData >> (48 + 160));
                          return ValidationData(aggregator, validAfter, validUntil);
                      }
                  // intersect account and paymaster ranges.
                      function _intersectTimeRange(uint256 validationData, uint256 paymasterValidationData) pure returns (ValidationData memory) {
                          ValidationData memory accountValidationData = _parseValidationData(validationData);
                          ValidationData memory pmValidationData = _parseValidationData(paymasterValidationData);
                          address aggregator = accountValidationData.aggregator;
                          if (aggregator == address(0)) {
                              aggregator = pmValidationData.aggregator;
                          }
                          uint48 validAfter = accountValidationData.validAfter;
                          uint48 validUntil = accountValidationData.validUntil;
                          uint48 pmValidAfter = pmValidationData.validAfter;
                          uint48 pmValidUntil = pmValidationData.validUntil;
                          if (validAfter < pmValidAfter) validAfter = pmValidAfter;
                          if (validUntil > pmValidUntil) validUntil = pmValidUntil;
                          return ValidationData(aggregator, validAfter, validUntil);
                      }
                  /**
                   * helper to pack the return value for validateUserOp
                   * @param data - the ValidationData to pack
                   */
                      function _packValidationData(ValidationData memory data) pure returns (uint256) {
                          return uint160(data.aggregator) | (uint256(data.validUntil) << 160) | (uint256(data.validAfter) << (160 + 48));
                      }
                  /**
                   * helper to pack the return value for validateUserOp, when not using an aggregator
                   * @param sigFailed - true for signature failure, false for success
                   * @param validUntil last timestamp this UserOperation is valid (or zero for infinite)
                   * @param validAfter first timestamp this UserOperation is valid
                   */
                      function _packValidationData(bool sigFailed, uint48 validUntil, uint48 validAfter) pure returns (uint256) {
                          return (sigFailed ? 1 : 0) | (uint256(validUntil) << 160) | (uint256(validAfter) << (160 + 48));
                      }
                  /**
                   * keccak function over calldata.
                   * @dev copy calldata into memory, do keccak and drop allocated memory. Strangely, this is more efficient than letting solidity do it.
                   */
                      function calldataKeccak(bytes calldata data) pure returns (bytes32 ret) {
                          assembly {
                              let mem := mload(0x40)
                              let len := data.length
                              calldatacopy(mem, data.offset, len)
                              ret := keccak256(mem, len)
                          }
                      }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  import "../interfaces/IEntryPoint.sol";
                  /**
                   * nonce management functionality
                   */
                  contract NonceManager is INonceManager {
                      /**
                       * The next valid sequence number for a given nonce key.
                       */
                      mapping(address => mapping(uint192 => uint256)) public nonceSequenceNumber;
                      function getNonce(address sender, uint192 key)
                      public view override returns (uint256 nonce) {
                          return nonceSequenceNumber[sender][key] | (uint256(key) << 64);
                      }
                      // allow an account to manually increment its own nonce.
                      // (mainly so that during construction nonce can be made non-zero,
                      // to "absorb" the gas cost of first nonce increment to 1st transaction (construction),
                      // not to 2nd transaction)
                      function incrementNonce(uint192 key) public override {
                          nonceSequenceNumber[msg.sender][key]++;
                      }
                      /**
                       * validate nonce uniqueness for this account.
                       * called just after validateUserOp()
                       */
                      function _validateAndUpdateNonce(address sender, uint256 nonce) internal returns (bool) {
                          uint192 key = uint192(nonce >> 64);
                          uint64 seq = uint64(nonce);
                          return nonceSequenceNumber[sender][key]++ == seq;
                      }
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  /**
                   * helper contract for EntryPoint, to call userOp.initCode from a "neutral" address,
                   * which is explicitly not the entryPoint itself.
                   */
                  contract SenderCreator {
                      /**
                       * call the "initCode" factory to create and return the sender account address
                       * @param initCode the initCode value from a UserOp. contains 20 bytes of factory address, followed by calldata
                       * @return sender the returned address of the created account, or zero address on failure.
                       */
                      function createSender(bytes calldata initCode) external returns (address sender) {
                          address factory = address(bytes20(initCode[0 : 20]));
                          bytes memory initCallData = initCode[20 :];
                          bool success;
                          /* solhint-disable no-inline-assembly */
                          assembly {
                              success := call(gas(), factory, 0, add(initCallData, 0x20), mload(initCallData), 0, 32)
                              sender := mload(0)
                          }
                          if (!success) {
                              sender = address(0);
                          }
                      }
                  }
                  // SPDX-License-Identifier: GPL-3.0-only
                  pragma solidity ^0.8.12;
                  import "../interfaces/IStakeManager.sol";
                  /* solhint-disable avoid-low-level-calls */
                  /* solhint-disable not-rely-on-time */
                  /**
                   * manage deposits and stakes.
                   * deposit is just a balance used to pay for UserOperations (either by a paymaster or an account)
                   * stake is value locked for at least "unstakeDelay" by a paymaster.
                   */
                  abstract contract StakeManager is IStakeManager {
                      /// maps paymaster to their deposits and stakes
                      mapping(address => DepositInfo) public deposits;
                      /// @inheritdoc IStakeManager
                      function getDepositInfo(address account) public view returns (DepositInfo memory info) {
                          return deposits[account];
                      }
                      // internal method to return just the stake info
                      function _getStakeInfo(address addr) internal view returns (StakeInfo memory info) {
                          DepositInfo storage depositInfo = deposits[addr];
                          info.stake = depositInfo.stake;
                          info.unstakeDelaySec = depositInfo.unstakeDelaySec;
                      }
                      /// return the deposit (for gas payment) of the account
                      function balanceOf(address account) public view returns (uint256) {
                          return deposits[account].deposit;
                      }
                      receive() external payable {
                          depositTo(msg.sender);
                      }
                      function _incrementDeposit(address account, uint256 amount) internal {
                          DepositInfo storage info = deposits[account];
                          uint256 newAmount = info.deposit + amount;
                          require(newAmount <= type(uint112).max, "deposit overflow");
                          info.deposit = uint112(newAmount);
                      }
                      /**
                       * add to the deposit of the given account
                       */
                      function depositTo(address account) public payable {
                          _incrementDeposit(account, msg.value);
                          DepositInfo storage info = deposits[account];
                          emit Deposited(account, info.deposit);
                      }
                      /**
                       * add to the account's stake - amount and delay
                       * any pending unstake is first cancelled.
                       * @param unstakeDelaySec the new lock duration before the deposit can be withdrawn.
                       */
                      function addStake(uint32 unstakeDelaySec) public payable {
                          DepositInfo storage info = deposits[msg.sender];
                          require(unstakeDelaySec > 0, "must specify unstake delay");
                          require(unstakeDelaySec >= info.unstakeDelaySec, "cannot decrease unstake time");
                          uint256 stake = info.stake + msg.value;
                          require(stake > 0, "no stake specified");
                          require(stake <= type(uint112).max, "stake overflow");
                          deposits[msg.sender] = DepositInfo(
                              info.deposit,
                              true,
                              uint112(stake),
                              unstakeDelaySec,
                              0
                          );
                          emit StakeLocked(msg.sender, stake, unstakeDelaySec);
                      }
                      /**
                       * attempt to unlock the stake.
                       * the value can be withdrawn (using withdrawStake) after the unstake delay.
                       */
                      function unlockStake() external {
                          DepositInfo storage info = deposits[msg.sender];
                          require(info.unstakeDelaySec != 0, "not staked");
                          require(info.staked, "already unstaking");
                          uint48 withdrawTime = uint48(block.timestamp) + info.unstakeDelaySec;
                          info.withdrawTime = withdrawTime;
                          info.staked = false;
                          emit StakeUnlocked(msg.sender, withdrawTime);
                      }
                      /**
                       * withdraw from the (unlocked) stake.
                       * must first call unlockStake and wait for the unstakeDelay to pass
                       * @param withdrawAddress the address to send withdrawn value.
                       */
                      function withdrawStake(address payable withdrawAddress) external {
                          DepositInfo storage info = deposits[msg.sender];
                          uint256 stake = info.stake;
                          require(stake > 0, "No stake to withdraw");
                          require(info.withdrawTime > 0, "must call unlockStake() first");
                          require(info.withdrawTime <= block.timestamp, "Stake withdrawal is not due");
                          info.unstakeDelaySec = 0;
                          info.withdrawTime = 0;
                          info.stake = 0;
                          emit StakeWithdrawn(msg.sender, withdrawAddress, stake);
                          (bool success,) = withdrawAddress.call{value : stake}("");
                          require(success, "failed to withdraw stake");
                      }
                      /**
                       * withdraw from the deposit.
                       * @param withdrawAddress the address to send withdrawn value.
                       * @param withdrawAmount the amount to withdraw.
                       */
                      function withdrawTo(address payable withdrawAddress, uint256 withdrawAmount) external {
                          DepositInfo storage info = deposits[msg.sender];
                          require(withdrawAmount <= info.deposit, "Withdraw amount too large");
                          info.deposit = uint112(info.deposit - withdrawAmount);
                          emit Withdrawn(msg.sender, withdrawAddress, withdrawAmount);
                          (bool success,) = withdrawAddress.call{value : withdrawAmount}("");
                          require(success, "failed to withdraw");
                      }
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  import "./UserOperation.sol";
                  interface IAccount {
                      /**
                       * Validate user's signature and nonce
                       * the entryPoint will make the call to the recipient only if this validation call returns successfully.
                       * signature failure should be reported by returning SIG_VALIDATION_FAILED (1).
                       * This allows making a "simulation call" without a valid signature
                       * Other failures (e.g. nonce mismatch, or invalid signature format) should still revert to signal failure.
                       *
                       * @dev Must validate caller is the entryPoint.
                       *      Must validate the signature and nonce
                       * @param userOp the operation that is about to be executed.
                       * @param userOpHash hash of the user's request data. can be used as the basis for signature.
                       * @param missingAccountFunds missing funds on the account's deposit in the entrypoint.
                       *      This is the minimum amount to transfer to the sender(entryPoint) to be able to make the call.
                       *      The excess is left as a deposit in the entrypoint, for future calls.
                       *      can be withdrawn anytime using "entryPoint.withdrawTo()"
                       *      In case there is a paymaster in the request (or the current deposit is high enough), this value will be zero.
                       * @return validationData packaged ValidationData structure. use `_packValidationData` and `_unpackValidationData` to encode and decode
                       *      <20-byte> sigAuthorizer - 0 for valid signature, 1 to mark signature failure,
                       *         otherwise, an address of an "authorizer" contract.
                       *      <6-byte> validUntil - last timestamp this operation is valid. 0 for "indefinite"
                       *      <6-byte> validAfter - first timestamp this operation is valid
                       *      If an account doesn't use time-range, it is enough to return SIG_VALIDATION_FAILED value (1) for signature failure.
                       *      Note that the validation code cannot use block.timestamp (or block.number) directly.
                       */
                      function validateUserOp(UserOperation calldata userOp, bytes32 userOpHash, uint256 missingAccountFunds)
                      external returns (uint256 validationData);
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  import "./UserOperation.sol";
                  /**
                   * Aggregated Signatures validator.
                   */
                  interface IAggregator {
                      /**
                       * validate aggregated signature.
                       * revert if the aggregated signature does not match the given list of operations.
                       */
                      function validateSignatures(UserOperation[] calldata userOps, bytes calldata signature) external view;
                      /**
                       * validate signature of a single userOp
                       * This method is should be called by bundler after EntryPoint.simulateValidation() returns (reverts) with ValidationResultWithAggregation
                       * First it validates the signature over the userOp. Then it returns data to be used when creating the handleOps.
                       * @param userOp the userOperation received from the user.
                       * @return sigForUserOp the value to put into the signature field of the userOp when calling handleOps.
                       *    (usually empty, unless account and aggregator support some kind of "multisig"
                       */
                      function validateUserOpSignature(UserOperation calldata userOp)
                      external view returns (bytes memory sigForUserOp);
                      /**
                       * aggregate multiple signatures into a single value.
                       * This method is called off-chain to calculate the signature to pass with handleOps()
                       * bundler MAY use optimized custom code perform this aggregation
                       * @param userOps array of UserOperations to collect the signatures from.
                       * @return aggregatedSignature the aggregated signature
                       */
                      function aggregateSignatures(UserOperation[] calldata userOps) external view returns (bytes memory aggregatedSignature);
                  }
                  /**
                   ** Account-Abstraction (EIP-4337) singleton EntryPoint implementation.
                   ** Only one instance required on each chain.
                   **/
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  /* solhint-disable avoid-low-level-calls */
                  /* solhint-disable no-inline-assembly */
                  /* solhint-disable reason-string */
                  import "./UserOperation.sol";
                  import "./IStakeManager.sol";
                  import "./IAggregator.sol";
                  import "./INonceManager.sol";
                  interface IEntryPoint is IStakeManager, INonceManager {
                      /***
                       * An event emitted after each successful request
                       * @param userOpHash - unique identifier for the request (hash its entire content, except signature).
                       * @param sender - the account that generates this request.
                       * @param paymaster - if non-null, the paymaster that pays for this request.
                       * @param nonce - the nonce value from the request.
                       * @param success - true if the sender transaction succeeded, false if reverted.
                       * @param actualGasCost - actual amount paid (by account or paymaster) for this UserOperation.
                       * @param actualGasUsed - total gas used by this UserOperation (including preVerification, creation, validation and execution).
                       */
                      event UserOperationEvent(bytes32 indexed userOpHash, address indexed sender, address indexed paymaster, uint256 nonce, bool success, uint256 actualGasCost, uint256 actualGasUsed);
                      /**
                       * account "sender" was deployed.
                       * @param userOpHash the userOp that deployed this account. UserOperationEvent will follow.
                       * @param sender the account that is deployed
                       * @param factory the factory used to deploy this account (in the initCode)
                       * @param paymaster the paymaster used by this UserOp
                       */
                      event AccountDeployed(bytes32 indexed userOpHash, address indexed sender, address factory, address paymaster);
                      /**
                       * An event emitted if the UserOperation "callData" reverted with non-zero length
                       * @param userOpHash the request unique identifier.
                       * @param sender the sender of this request
                       * @param nonce the nonce used in the request
                       * @param revertReason - the return bytes from the (reverted) call to "callData".
                       */
                      event UserOperationRevertReason(bytes32 indexed userOpHash, address indexed sender, uint256 nonce, bytes revertReason);
                      /**
                       * an event emitted by handleOps(), before starting the execution loop.
                       * any event emitted before this event, is part of the validation.
                       */
                      event BeforeExecution();
                      /**
                       * signature aggregator used by the following UserOperationEvents within this bundle.
                       */
                      event SignatureAggregatorChanged(address indexed aggregator);
                      /**
                       * a custom revert error of handleOps, to identify the offending op.
                       *  NOTE: if simulateValidation passes successfully, there should be no reason for handleOps to fail on it.
                       *  @param opIndex - index into the array of ops to the failed one (in simulateValidation, this is always zero)
                       *  @param reason - revert reason
                       *      The string starts with a unique code "AAmn", where "m" is "1" for factory, "2" for account and "3" for paymaster issues,
                       *      so a failure can be attributed to the correct entity.
                       *   Should be caught in off-chain handleOps simulation and not happen on-chain.
                       *   Useful for mitigating DoS attempts against batchers or for troubleshooting of factory/account/paymaster reverts.
                       */
                      error FailedOp(uint256 opIndex, string reason);
                      /**
                       * error case when a signature aggregator fails to verify the aggregated signature it had created.
                       */
                      error SignatureValidationFailed(address aggregator);
                      /**
                       * Successful result from simulateValidation.
                       * @param returnInfo gas and time-range returned values
                       * @param senderInfo stake information about the sender
                       * @param factoryInfo stake information about the factory (if any)
                       * @param paymasterInfo stake information about the paymaster (if any)
                       */
                      error ValidationResult(ReturnInfo returnInfo,
                          StakeInfo senderInfo, StakeInfo factoryInfo, StakeInfo paymasterInfo);
                      /**
                       * Successful result from simulateValidation, if the account returns a signature aggregator
                       * @param returnInfo gas and time-range returned values
                       * @param senderInfo stake information about the sender
                       * @param factoryInfo stake information about the factory (if any)
                       * @param paymasterInfo stake information about the paymaster (if any)
                       * @param aggregatorInfo signature aggregation info (if the account requires signature aggregator)
                       *      bundler MUST use it to verify the signature, or reject the UserOperation
                       */
                      error ValidationResultWithAggregation(ReturnInfo returnInfo,
                          StakeInfo senderInfo, StakeInfo factoryInfo, StakeInfo paymasterInfo,
                          AggregatorStakeInfo aggregatorInfo);
                      /**
                       * return value of getSenderAddress
                       */
                      error SenderAddressResult(address sender);
                      /**
                       * return value of simulateHandleOp
                       */
                      error ExecutionResult(uint256 preOpGas, uint256 paid, uint48 validAfter, uint48 validUntil, bool targetSuccess, bytes targetResult);
                      //UserOps handled, per aggregator
                      struct UserOpsPerAggregator {
                          UserOperation[] userOps;
                          // aggregator address
                          IAggregator aggregator;
                          // aggregated signature
                          bytes signature;
                      }
                      /**
                       * Execute a batch of UserOperation.
                       * no signature aggregator is used.
                       * if any account requires an aggregator (that is, it returned an aggregator when
                       * performing simulateValidation), then handleAggregatedOps() must be used instead.
                       * @param ops the operations to execute
                       * @param beneficiary the address to receive the fees
                       */
                      function handleOps(UserOperation[] calldata ops, address payable beneficiary) external;
                      /**
                       * Execute a batch of UserOperation with Aggregators
                       * @param opsPerAggregator the operations to execute, grouped by aggregator (or address(0) for no-aggregator accounts)
                       * @param beneficiary the address to receive the fees
                       */
                      function handleAggregatedOps(
                          UserOpsPerAggregator[] calldata opsPerAggregator,
                          address payable beneficiary
                      ) external;
                      /**
                       * generate a request Id - unique identifier for this request.
                       * the request ID is a hash over the content of the userOp (except the signature), the entrypoint and the chainid.
                       */
                      function getUserOpHash(UserOperation calldata userOp) external view returns (bytes32);
                      /**
                       * Simulate a call to account.validateUserOp and paymaster.validatePaymasterUserOp.
                       * @dev this method always revert. Successful result is ValidationResult error. other errors are failures.
                       * @dev The node must also verify it doesn't use banned opcodes, and that it doesn't reference storage outside the account's data.
                       * @param userOp the user operation to validate.
                       */
                      function simulateValidation(UserOperation calldata userOp) external;
                      /**
                       * gas and return values during simulation
                       * @param preOpGas the gas used for validation (including preValidationGas)
                       * @param prefund the required prefund for this operation
                       * @param sigFailed validateUserOp's (or paymaster's) signature check failed
                       * @param validAfter - first timestamp this UserOp is valid (merging account and paymaster time-range)
                       * @param validUntil - last timestamp this UserOp is valid (merging account and paymaster time-range)
                       * @param paymasterContext returned by validatePaymasterUserOp (to be passed into postOp)
                       */
                      struct ReturnInfo {
                          uint256 preOpGas;
                          uint256 prefund;
                          bool sigFailed;
                          uint48 validAfter;
                          uint48 validUntil;
                          bytes paymasterContext;
                      }
                      /**
                       * returned aggregated signature info.
                       * the aggregator returned by the account, and its current stake.
                       */
                      struct AggregatorStakeInfo {
                          address aggregator;
                          StakeInfo stakeInfo;
                      }
                      /**
                       * Get counterfactual sender address.
                       *  Calculate the sender contract address that will be generated by the initCode and salt in the UserOperation.
                       * this method always revert, and returns the address in SenderAddressResult error
                       * @param initCode the constructor code to be passed into the UserOperation.
                       */
                      function getSenderAddress(bytes memory initCode) external;
                      /**
                       * simulate full execution of a UserOperation (including both validation and target execution)
                       * this method will always revert with "ExecutionResult".
                       * it performs full validation of the UserOperation, but ignores signature error.
                       * an optional target address is called after the userop succeeds, and its value is returned
                       * (before the entire call is reverted)
                       * Note that in order to collect the the success/failure of the target call, it must be executed
                       * with trace enabled to track the emitted events.
                       * @param op the UserOperation to simulate
                       * @param target if nonzero, a target address to call after userop simulation. If called, the targetSuccess and targetResult
                       *        are set to the return from that call.
                       * @param targetCallData callData to pass to target address
                       */
                      function simulateHandleOp(UserOperation calldata op, address target, bytes calldata targetCallData) external;
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  interface INonceManager {
                      /**
                       * Return the next nonce for this sender.
                       * Within a given key, the nonce values are sequenced (starting with zero, and incremented by one on each userop)
                       * But UserOp with different keys can come with arbitrary order.
                       *
                       * @param sender the account address
                       * @param key the high 192 bit of the nonce
                       * @return nonce a full nonce to pass for next UserOp with this sender.
                       */
                      function getNonce(address sender, uint192 key)
                      external view returns (uint256 nonce);
                      /**
                       * Manually increment the nonce of the sender.
                       * This method is exposed just for completeness..
                       * Account does NOT need to call it, neither during validation, nor elsewhere,
                       * as the EntryPoint will update the nonce regardless.
                       * Possible use-case is call it with various keys to "initialize" their nonces to one, so that future
                       * UserOperations will not pay extra for the first transaction with a given key.
                       */
                      function incrementNonce(uint192 key) external;
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  import "./UserOperation.sol";
                  /**
                   * the interface exposed by a paymaster contract, who agrees to pay the gas for user's operations.
                   * a paymaster must hold a stake to cover the required entrypoint stake and also the gas for the transaction.
                   */
                  interface IPaymaster {
                      enum PostOpMode {
                          opSucceeded, // user op succeeded
                          opReverted, // user op reverted. still has to pay for gas.
                          postOpReverted //user op succeeded, but caused postOp to revert. Now it's a 2nd call, after user's op was deliberately reverted.
                      }
                      /**
                       * payment validation: check if paymaster agrees to pay.
                       * Must verify sender is the entryPoint.
                       * Revert to reject this request.
                       * Note that bundlers will reject this method if it changes the state, unless the paymaster is trusted (whitelisted)
                       * The paymaster pre-pays using its deposit, and receive back a refund after the postOp method returns.
                       * @param userOp the user operation
                       * @param userOpHash hash of the user's request data.
                       * @param maxCost the maximum cost of this transaction (based on maximum gas and gas price from userOp)
                       * @return context value to send to a postOp
                       *      zero length to signify postOp is not required.
                       * @return validationData signature and time-range of this operation, encoded the same as the return value of validateUserOperation
                       *      <20-byte> sigAuthorizer - 0 for valid signature, 1 to mark signature failure,
                       *         otherwise, an address of an "authorizer" contract.
                       *      <6-byte> validUntil - last timestamp this operation is valid. 0 for "indefinite"
                       *      <6-byte> validAfter - first timestamp this operation is valid
                       *      Note that the validation code cannot use block.timestamp (or block.number) directly.
                       */
                      function validatePaymasterUserOp(UserOperation calldata userOp, bytes32 userOpHash, uint256 maxCost)
                      external returns (bytes memory context, uint256 validationData);
                      /**
                       * post-operation handler.
                       * Must verify sender is the entryPoint
                       * @param mode enum with the following options:
                       *      opSucceeded - user operation succeeded.
                       *      opReverted  - user op reverted. still has to pay for gas.
                       *      postOpReverted - user op succeeded, but caused postOp (in mode=opSucceeded) to revert.
                       *                       Now this is the 2nd call, after user's op was deliberately reverted.
                       * @param context - the context value returned by validatePaymasterUserOp
                       * @param actualGasCost - actual gas used so far (without this postOp call).
                       */
                      function postOp(PostOpMode mode, bytes calldata context, uint256 actualGasCost) external;
                  }
                  // SPDX-License-Identifier: GPL-3.0-only
                  pragma solidity ^0.8.12;
                  /**
                   * manage deposits and stakes.
                   * deposit is just a balance used to pay for UserOperations (either by a paymaster or an account)
                   * stake is value locked for at least "unstakeDelay" by the staked entity.
                   */
                  interface IStakeManager {
                      event Deposited(
                          address indexed account,
                          uint256 totalDeposit
                      );
                      event Withdrawn(
                          address indexed account,
                          address withdrawAddress,
                          uint256 amount
                      );
                      /// Emitted when stake or unstake delay are modified
                      event StakeLocked(
                          address indexed account,
                          uint256 totalStaked,
                          uint256 unstakeDelaySec
                      );
                      /// Emitted once a stake is scheduled for withdrawal
                      event StakeUnlocked(
                          address indexed account,
                          uint256 withdrawTime
                      );
                      event StakeWithdrawn(
                          address indexed account,
                          address withdrawAddress,
                          uint256 amount
                      );
                      /**
                       * @param deposit the entity's deposit
                       * @param staked true if this entity is staked.
                       * @param stake actual amount of ether staked for this entity.
                       * @param unstakeDelaySec minimum delay to withdraw the stake.
                       * @param withdrawTime - first block timestamp where 'withdrawStake' will be callable, or zero if already locked
                       * @dev sizes were chosen so that (deposit,staked, stake) fit into one cell (used during handleOps)
                       *    and the rest fit into a 2nd cell.
                       *    112 bit allows for 10^15 eth
                       *    48 bit for full timestamp
                       *    32 bit allows 150 years for unstake delay
                       */
                      struct DepositInfo {
                          uint112 deposit;
                          bool staked;
                          uint112 stake;
                          uint32 unstakeDelaySec;
                          uint48 withdrawTime;
                      }
                      //API struct used by getStakeInfo and simulateValidation
                      struct StakeInfo {
                          uint256 stake;
                          uint256 unstakeDelaySec;
                      }
                      /// @return info - full deposit information of given account
                      function getDepositInfo(address account) external view returns (DepositInfo memory info);
                      /// @return the deposit (for gas payment) of the account
                      function balanceOf(address account) external view returns (uint256);
                      /**
                       * add to the deposit of the given account
                       */
                      function depositTo(address account) external payable;
                      /**
                       * add to the account's stake - amount and delay
                       * any pending unstake is first cancelled.
                       * @param _unstakeDelaySec the new lock duration before the deposit can be withdrawn.
                       */
                      function addStake(uint32 _unstakeDelaySec) external payable;
                      /**
                       * attempt to unlock the stake.
                       * the value can be withdrawn (using withdrawStake) after the unstake delay.
                       */
                      function unlockStake() external;
                      /**
                       * withdraw from the (unlocked) stake.
                       * must first call unlockStake and wait for the unstakeDelay to pass
                       * @param withdrawAddress the address to send withdrawn value.
                       */
                      function withdrawStake(address payable withdrawAddress) external;
                      /**
                       * withdraw from the deposit.
                       * @param withdrawAddress the address to send withdrawn value.
                       * @param withdrawAmount the amount to withdraw.
                       */
                      function withdrawTo(address payable withdrawAddress, uint256 withdrawAmount) external;
                  }
                  // SPDX-License-Identifier: GPL-3.0
                  pragma solidity ^0.8.12;
                  /* solhint-disable no-inline-assembly */
                  import {calldataKeccak} from "../core/Helpers.sol";
                  /**
                   * User Operation struct
                   * @param sender the sender account of this request.
                       * @param nonce unique value the sender uses to verify it is not a replay.
                       * @param initCode if set, the account contract will be created by this constructor/
                       * @param callData the method call to execute on this account.
                       * @param callGasLimit the gas limit passed to the callData method call.
                       * @param verificationGasLimit gas used for validateUserOp and validatePaymasterUserOp.
                       * @param preVerificationGas gas not calculated by the handleOps method, but added to the gas paid. Covers batch overhead.
                       * @param maxFeePerGas same as EIP-1559 gas parameter.
                       * @param maxPriorityFeePerGas same as EIP-1559 gas parameter.
                       * @param paymasterAndData if set, this field holds the paymaster address and paymaster-specific data. the paymaster will pay for the transaction instead of the sender.
                       * @param signature sender-verified signature over the entire request, the EntryPoint address and the chain ID.
                       */
                      struct UserOperation {
                          address sender;
                          uint256 nonce;
                          bytes initCode;
                          bytes callData;
                          uint256 callGasLimit;
                          uint256 verificationGasLimit;
                          uint256 preVerificationGas;
                          uint256 maxFeePerGas;
                          uint256 maxPriorityFeePerGas;
                          bytes paymasterAndData;
                          bytes signature;
                      }
                  /**
                   * Utility functions helpful when working with UserOperation structs.
                   */
                  library UserOperationLib {
                      function getSender(UserOperation calldata userOp) internal pure returns (address) {
                          address data;
                          //read sender from userOp, which is first userOp member (saves 800 gas...)
                          assembly {data := calldataload(userOp)}
                          return address(uint160(data));
                      }
                      //relayer/block builder might submit the TX with higher priorityFee, but the user should not
                      // pay above what he signed for.
                      function gasPrice(UserOperation calldata userOp) internal view returns (uint256) {
                      unchecked {
                          uint256 maxFeePerGas = userOp.maxFeePerGas;
                          uint256 maxPriorityFeePerGas = userOp.maxPriorityFeePerGas;
                          if (maxFeePerGas == maxPriorityFeePerGas) {
                              //legacy mode (for networks that don't support basefee opcode)
                              return maxFeePerGas;
                          }
                          return min(maxFeePerGas, maxPriorityFeePerGas + block.basefee);
                      }
                      }
                      function pack(UserOperation calldata userOp) internal pure returns (bytes memory ret) {
                          address sender = getSender(userOp);
                          uint256 nonce = userOp.nonce;
                          bytes32 hashInitCode = calldataKeccak(userOp.initCode);
                          bytes32 hashCallData = calldataKeccak(userOp.callData);
                          uint256 callGasLimit = userOp.callGasLimit;
                          uint256 verificationGasLimit = userOp.verificationGasLimit;
                          uint256 preVerificationGas = userOp.preVerificationGas;
                          uint256 maxFeePerGas = userOp.maxFeePerGas;
                          uint256 maxPriorityFeePerGas = userOp.maxPriorityFeePerGas;
                          bytes32 hashPaymasterAndData = calldataKeccak(userOp.paymasterAndData);
                          return abi.encode(
                              sender, nonce,
                              hashInitCode, hashCallData,
                              callGasLimit, verificationGasLimit, preVerificationGas,
                              maxFeePerGas, maxPriorityFeePerGas,
                              hashPaymasterAndData
                          );
                      }
                      function hash(UserOperation calldata userOp) internal pure returns (bytes32) {
                          return keccak256(pack(userOp));
                      }
                      function min(uint256 a, uint256 b) internal pure returns (uint256) {
                          return a < b ? a : b;
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.5 <0.9.0;
                  // solhint-disable no-inline-assembly
                  /**
                   * Utility functions helpful when making different kinds of contract calls in Solidity.
                   */
                  library Exec {
                      function call(
                          address to,
                          uint256 value,
                          bytes memory data,
                          uint256 txGas
                      ) internal returns (bool success) {
                          assembly {
                              success := call(txGas, to, value, add(data, 0x20), mload(data), 0, 0)
                          }
                      }
                      function staticcall(
                          address to,
                          bytes memory data,
                          uint256 txGas
                      ) internal view returns (bool success) {
                          assembly {
                              success := staticcall(txGas, to, add(data, 0x20), mload(data), 0, 0)
                          }
                      }
                      function delegateCall(
                          address to,
                          bytes memory data,
                          uint256 txGas
                      ) internal returns (bool success) {
                          assembly {
                              success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
                          }
                      }
                      // get returned data from last call or calldelegate
                      function getReturnData(uint256 maxLen) internal pure returns (bytes memory returnData) {
                          assembly {
                              let len := returndatasize()
                              if gt(len, maxLen) {
                                  len := maxLen
                              }
                              let ptr := mload(0x40)
                              mstore(0x40, add(ptr, add(len, 0x20)))
                              mstore(ptr, len)
                              returndatacopy(add(ptr, 0x20), 0, len)
                              returnData := ptr
                          }
                      }
                      // revert with explicit byte array (probably reverted info from call)
                      function revertWithData(bytes memory returnData) internal pure {
                          assembly {
                              revert(add(returnData, 32), mload(returnData))
                          }
                      }
                      function callAndRevert(address to, bytes memory data, uint256 maxLen) internal {
                          bool success = call(to,0,data,gasleft());
                          if (!success) {
                              revertWithData(getReturnData(maxLen));
                          }
                      }
                  }
                  

                  File 2 of 3: FiatTokenProxy
                  pragma solidity ^0.4.24;
                  
                  // File: zos-lib/contracts/upgradeability/Proxy.sol
                  
                  /**
                   * @title Proxy
                   * @dev Implements delegation of calls to other contracts, with proper
                   * forwarding of return values and bubbling of failures.
                   * It defines a fallback function that delegates all calls to the address
                   * returned by the abstract _implementation() internal function.
                   */
                  contract Proxy {
                    /**
                     * @dev Fallback function.
                     * Implemented entirely in `_fallback`.
                     */
                    function () payable external {
                      _fallback();
                    }
                  
                    /**
                     * @return The Address of the implementation.
                     */
                    function _implementation() internal view returns (address);
                  
                    /**
                     * @dev Delegates execution to an implementation contract.
                     * This is a low level function that doesn't return to its internal call site.
                     * It will return to the external caller whatever the implementation returns.
                     * @param implementation Address to delegate.
                     */
                    function _delegate(address implementation) internal {
                      assembly {
                        // Copy msg.data. We take full control of memory in this inline assembly
                        // block because it will not return to Solidity code. We overwrite the
                        // Solidity scratch pad at memory position 0.
                        calldatacopy(0, 0, calldatasize)
                  
                        // Call the implementation.
                        // out and outsize are 0 because we don't know the size yet.
                        let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                  
                        // Copy the returned data.
                        returndatacopy(0, 0, returndatasize)
                  
                        switch result
                        // delegatecall returns 0 on error.
                        case 0 { revert(0, returndatasize) }
                        default { return(0, returndatasize) }
                      }
                    }
                  
                    /**
                     * @dev Function that is run as the first thing in the fallback function.
                     * Can be redefined in derived contracts to add functionality.
                     * Redefinitions must call super._willFallback().
                     */
                    function _willFallback() internal {
                    }
                  
                    /**
                     * @dev fallback implementation.
                     * Extracted to enable manual triggering.
                     */
                    function _fallback() internal {
                      _willFallback();
                      _delegate(_implementation());
                    }
                  }
                  
                  // File: openzeppelin-solidity/contracts/AddressUtils.sol
                  
                  /**
                   * Utility library of inline functions on addresses
                   */
                  library AddressUtils {
                  
                    /**
                     * Returns whether the target address is a contract
                     * @dev This function will return false if invoked during the constructor of a contract,
                     * as the code is not actually created until after the constructor finishes.
                     * @param addr address to check
                     * @return whether the target address is a contract
                     */
                    function isContract(address addr) internal view returns (bool) {
                      uint256 size;
                      // XXX Currently there is no better way to check if there is a contract in an address
                      // than to check the size of the code at that address.
                      // See https://ethereum.stackexchange.com/a/14016/36603
                      // for more details about how this works.
                      // TODO Check this again before the Serenity release, because all addresses will be
                      // contracts then.
                      // solium-disable-next-line security/no-inline-assembly
                      assembly { size := extcodesize(addr) }
                      return size > 0;
                    }
                  
                  }
                  
                  // File: zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol
                  
                  /**
                   * @title UpgradeabilityProxy
                   * @dev This contract implements a proxy that allows to change the
                   * implementation address to which it will delegate.
                   * Such a change is called an implementation upgrade.
                   */
                  contract UpgradeabilityProxy is Proxy {
                    /**
                     * @dev Emitted when the implementation is upgraded.
                     * @param implementation Address of the new implementation.
                     */
                    event Upgraded(address implementation);
                  
                    /**
                     * @dev Storage slot with the address of the current implementation.
                     * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                     * validated in the constructor.
                     */
                    bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                  
                    /**
                     * @dev Contract constructor.
                     * @param _implementation Address of the initial implementation.
                     */
                    constructor(address _implementation) public {
                      assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                  
                      _setImplementation(_implementation);
                    }
                  
                    /**
                     * @dev Returns the current implementation.
                     * @return Address of the current implementation
                     */
                    function _implementation() internal view returns (address impl) {
                      bytes32 slot = IMPLEMENTATION_SLOT;
                      assembly {
                        impl := sload(slot)
                      }
                    }
                  
                    /**
                     * @dev Upgrades the proxy to a new implementation.
                     * @param newImplementation Address of the new implementation.
                     */
                    function _upgradeTo(address newImplementation) internal {
                      _setImplementation(newImplementation);
                      emit Upgraded(newImplementation);
                    }
                  
                    /**
                     * @dev Sets the implementation address of the proxy.
                     * @param newImplementation Address of the new implementation.
                     */
                    function _setImplementation(address newImplementation) private {
                      require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                  
                      bytes32 slot = IMPLEMENTATION_SLOT;
                  
                      assembly {
                        sstore(slot, newImplementation)
                      }
                    }
                  }
                  
                  // File: zos-lib/contracts/upgradeability/AdminUpgradeabilityProxy.sol
                  
                  /**
                   * @title AdminUpgradeabilityProxy
                   * @dev This contract combines an upgradeability proxy with an authorization
                   * mechanism for administrative tasks.
                   * All external functions in this contract must be guarded by the
                   * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                   * feature proposal that would enable this to be done automatically.
                   */
                  contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                    /**
                     * @dev Emitted when the administration has been transferred.
                     * @param previousAdmin Address of the previous admin.
                     * @param newAdmin Address of the new admin.
                     */
                    event AdminChanged(address previousAdmin, address newAdmin);
                  
                    /**
                     * @dev Storage slot with the admin of the contract.
                     * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                     * validated in the constructor.
                     */
                    bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                  
                    /**
                     * @dev Modifier to check whether the `msg.sender` is the admin.
                     * If it is, it will run the function. Otherwise, it will delegate the call
                     * to the implementation.
                     */
                    modifier ifAdmin() {
                      if (msg.sender == _admin()) {
                        _;
                      } else {
                        _fallback();
                      }
                    }
                  
                    /**
                     * Contract constructor.
                     * It sets the `msg.sender` as the proxy administrator.
                     * @param _implementation address of the initial implementation.
                     */
                    constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
                      assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                  
                      _setAdmin(msg.sender);
                    }
                  
                    /**
                     * @return The address of the proxy admin.
                     */
                    function admin() external view ifAdmin returns (address) {
                      return _admin();
                    }
                  
                    /**
                     * @return The address of the implementation.
                     */
                    function implementation() external view ifAdmin returns (address) {
                      return _implementation();
                    }
                  
                    /**
                     * @dev Changes the admin of the proxy.
                     * Only the current admin can call this function.
                     * @param newAdmin Address to transfer proxy administration to.
                     */
                    function changeAdmin(address newAdmin) external ifAdmin {
                      require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                      emit AdminChanged(_admin(), newAdmin);
                      _setAdmin(newAdmin);
                    }
                  
                    /**
                     * @dev Upgrade the backing implementation of the proxy.
                     * Only the admin can call this function.
                     * @param newImplementation Address of the new implementation.
                     */
                    function upgradeTo(address newImplementation) external ifAdmin {
                      _upgradeTo(newImplementation);
                    }
                  
                    /**
                     * @dev Upgrade the backing implementation of the proxy and call a function
                     * on the new implementation.
                     * This is useful to initialize the proxied contract.
                     * @param newImplementation Address of the new implementation.
                     * @param data Data to send as msg.data in the low level call.
                     * It should include the signature and the parameters of the function to be
                     * called, as described in
                     * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
                     */
                    function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                      _upgradeTo(newImplementation);
                      require(address(this).call.value(msg.value)(data));
                    }
                  
                    /**
                     * @return The admin slot.
                     */
                    function _admin() internal view returns (address adm) {
                      bytes32 slot = ADMIN_SLOT;
                      assembly {
                        adm := sload(slot)
                      }
                    }
                  
                    /**
                     * @dev Sets the address of the proxy admin.
                     * @param newAdmin Address of the new proxy admin.
                     */
                    function _setAdmin(address newAdmin) internal {
                      bytes32 slot = ADMIN_SLOT;
                  
                      assembly {
                        sstore(slot, newAdmin)
                      }
                    }
                  
                    /**
                     * @dev Only fall back when the sender is not the admin.
                     */
                    function _willFallback() internal {
                      require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                      super._willFallback();
                    }
                  }
                  
                  // File: contracts/FiatTokenProxy.sol
                  
                  /**
                  * Copyright CENTRE SECZ 2018
                  *
                  * Permission is hereby granted, free of charge, to any person obtaining a copy 
                  * of this software and associated documentation files (the "Software"), to deal 
                  * in the Software without restriction, including without limitation the rights 
                  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
                  * copies of the Software, and to permit persons to whom the Software is furnished to 
                  * do so, subject to the following conditions:
                  *
                  * The above copyright notice and this permission notice shall be included in all 
                  * copies or substantial portions of the Software.
                  *
                  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
                  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
                  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
                  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
                  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
                  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
                  */
                  
                  pragma solidity ^0.4.24;
                  
                  
                  /**
                   * @title FiatTokenProxy
                   * @dev This contract proxies FiatToken calls and enables FiatToken upgrades
                  */ 
                  contract FiatTokenProxy is AdminUpgradeabilityProxy {
                      constructor(address _implementation) public AdminUpgradeabilityProxy(_implementation) {
                      }
                  }

                  File 3 of 3: FiatTokenV2_2
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { EIP712Domain } from "./EIP712Domain.sol"; // solhint-disable-line no-unused-import
                  import { Blacklistable } from "../v1/Blacklistable.sol"; // solhint-disable-line no-unused-import
                  import { FiatTokenV1 } from "../v1/FiatTokenV1.sol"; // solhint-disable-line no-unused-import
                  import { FiatTokenV2 } from "./FiatTokenV2.sol"; // solhint-disable-line no-unused-import
                  import { FiatTokenV2_1 } from "./FiatTokenV2_1.sol";
                  import { EIP712 } from "../util/EIP712.sol";
                  // solhint-disable func-name-mixedcase
                  /**
                   * @title FiatToken V2.2
                   * @notice ERC20 Token backed by fiat reserves, version 2.2
                   */
                  contract FiatTokenV2_2 is FiatTokenV2_1 {
                      /**
                       * @notice Initialize v2.2
                       * @param accountsToBlacklist   A list of accounts to migrate from the old blacklist
                       * @param newSymbol             New token symbol
                       * data structure to the new blacklist data structure.
                       */
                      function initializeV2_2(
                          address[] calldata accountsToBlacklist,
                          string calldata newSymbol
                      ) external {
                          // solhint-disable-next-line reason-string
                          require(_initializedVersion == 2);
                          // Update fiat token symbol
                          symbol = newSymbol;
                          // Add previously blacklisted accounts to the new blacklist data structure
                          // and remove them from the old blacklist data structure.
                          for (uint256 i = 0; i < accountsToBlacklist.length; i++) {
                              require(
                                  _deprecatedBlacklisted[accountsToBlacklist[i]],
                                  "FiatTokenV2_2: Blacklisting previously unblacklisted account!"
                              );
                              _blacklist(accountsToBlacklist[i]);
                              delete _deprecatedBlacklisted[accountsToBlacklist[i]];
                          }
                          _blacklist(address(this));
                          delete _deprecatedBlacklisted[address(this)];
                          _initializedVersion = 3;
                      }
                      /**
                       * @dev Internal function to get the current chain id.
                       * @return The current chain id.
                       */
                      function _chainId() internal virtual view returns (uint256) {
                          uint256 chainId;
                          assembly {
                              chainId := chainid()
                          }
                          return chainId;
                      }
                      /**
                       * @inheritdoc EIP712Domain
                       */
                      function _domainSeparator() internal override view returns (bytes32) {
                          return EIP712.makeDomainSeparator(name, "2", _chainId());
                      }
                      /**
                       * @notice Update allowance with a signed permit
                       * @dev EOA wallet signatures should be packed in the order of r, s, v.
                       * @param owner       Token owner's address (Authorizer)
                       * @param spender     Spender's address
                       * @param value       Amount of allowance
                       * @param deadline    The time at which the signature expires (unix time), or max uint256 value to signal no expiration
                       * @param signature   Signature bytes signed by an EOA wallet or a contract wallet
                       */
                      function permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          bytes memory signature
                      ) external whenNotPaused {
                          _permit(owner, spender, value, deadline, signature);
                      }
                      /**
                       * @notice Execute a transfer with a signed authorization
                       * @dev EOA wallet signatures should be packed in the order of r, s, v.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param signature     Signature bytes signed by an EOA wallet or a contract wallet
                       */
                      function transferWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          bytes memory signature
                      ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                          _transferWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              signature
                          );
                      }
                      /**
                       * @notice Receive a transfer with a signed authorization from the payer
                       * @dev This has an additional check to ensure that the payee's address
                       * matches the caller of this function to prevent front-running attacks.
                       * EOA wallet signatures should be packed in the order of r, s, v.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param signature     Signature bytes signed by an EOA wallet or a contract wallet
                       */
                      function receiveWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          bytes memory signature
                      ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                          _receiveWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              signature
                          );
                      }
                      /**
                       * @notice Attempt to cancel an authorization
                       * @dev Works only if the authorization is not yet used.
                       * EOA wallet signatures should be packed in the order of r, s, v.
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @param signature     Signature bytes signed by an EOA wallet or a contract wallet
                       */
                      function cancelAuthorization(
                          address authorizer,
                          bytes32 nonce,
                          bytes memory signature
                      ) external whenNotPaused {
                          _cancelAuthorization(authorizer, nonce, signature);
                      }
                      /**
                       * @dev Helper method that sets the blacklist state of an account on balanceAndBlacklistStates.
                       * If _shouldBlacklist is true, we apply a (1 << 255) bitmask with an OR operation on the
                       * account's balanceAndBlacklistState. This flips the high bit for the account to 1,
                       * indicating that the account is blacklisted.
                       *
                       * If _shouldBlacklist if false, we reset the account's balanceAndBlacklistStates to their
                       * balances. This clears the high bit for the account, indicating that the account is unblacklisted.
                       * @param _account         The address of the account.
                       * @param _shouldBlacklist True if the account should be blacklisted, false if the account should be unblacklisted.
                       */
                      function _setBlacklistState(address _account, bool _shouldBlacklist)
                          internal
                          override
                      {
                          balanceAndBlacklistStates[_account] = _shouldBlacklist
                              ? balanceAndBlacklistStates[_account] | (1 << 255)
                              : _balanceOf(_account);
                      }
                      /**
                       * @dev Helper method that sets the balance of an account on balanceAndBlacklistStates.
                       * Since balances are stored in the last 255 bits of the balanceAndBlacklistStates value,
                       * we need to ensure that the updated balance does not exceed (2^255 - 1).
                       * Since blacklisted accounts' balances cannot be updated, the method will also
                       * revert if the account is blacklisted
                       * @param _account The address of the account.
                       * @param _balance The new fiat token balance of the account (max: (2^255 - 1)).
                       */
                      function _setBalance(address _account, uint256 _balance) internal override {
                          require(
                              _balance <= ((1 << 255) - 1),
                              "FiatTokenV2_2: Balance exceeds (2^255 - 1)"
                          );
                          require(
                              !_isBlacklisted(_account),
                              "FiatTokenV2_2: Account is blacklisted"
                          );
                          balanceAndBlacklistStates[_account] = _balance;
                      }
                      /**
                       * @inheritdoc Blacklistable
                       */
                      function _isBlacklisted(address _account)
                          internal
                          override
                          view
                          returns (bool)
                      {
                          return balanceAndBlacklistStates[_account] >> 255 == 1;
                      }
                      /**
                       * @dev Helper method to obtain the balance of an account. Since balances
                       * are stored in the last 255 bits of the balanceAndBlacklistStates value,
                       * we apply a ((1 << 255) - 1) bit bitmask with an AND operation on the
                       * balanceAndBlacklistState to obtain the balance.
                       * @param _account  The address of the account.
                       * @return          The fiat token balance of the account.
                       */
                      function _balanceOf(address _account)
                          internal
                          override
                          view
                          returns (uint256)
                      {
                          return balanceAndBlacklistStates[_account] & ((1 << 255) - 1);
                      }
                      /**
                       * @inheritdoc FiatTokenV1
                       */
                      function approve(address spender, uint256 value)
                          external
                          override
                          whenNotPaused
                          returns (bool)
                      {
                          _approve(msg.sender, spender, value);
                          return true;
                      }
                      /**
                       * @inheritdoc FiatTokenV2
                       */
                      function permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external override whenNotPaused {
                          _permit(owner, spender, value, deadline, v, r, s);
                      }
                      /**
                       * @inheritdoc FiatTokenV2
                       */
                      function increaseAllowance(address spender, uint256 increment)
                          external
                          override
                          whenNotPaused
                          returns (bool)
                      {
                          _increaseAllowance(msg.sender, spender, increment);
                          return true;
                      }
                      /**
                       * @inheritdoc FiatTokenV2
                       */
                      function decreaseAllowance(address spender, uint256 decrement)
                          external
                          override
                          whenNotPaused
                          returns (bool)
                      {
                          _decreaseAllowance(msg.sender, spender, decrement);
                          return true;
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity >=0.6.2 <0.8.0;
                  /**
                   * @dev Collection of functions related to the address type
                   */
                  library Address {
                      /**
                       * @dev Returns true if `account` is a contract.
                       *
                       * [IMPORTANT]
                       * ====
                       * It is unsafe to assume that an address for which this function returns
                       * false is an externally-owned account (EOA) and not a contract.
                       *
                       * Among others, `isContract` will return false for the following
                       * types of addresses:
                       *
                       *  - an externally-owned account
                       *  - a contract in construction
                       *  - an address where a contract will be created
                       *  - an address where a contract lived, but was destroyed
                       * ====
                       */
                      function isContract(address account) internal view returns (bool) {
                          // This method relies on extcodesize, which returns 0 for contracts in
                          // construction, since the code is only stored at the end of the
                          // constructor execution.
                          uint256 size;
                          // solhint-disable-next-line no-inline-assembly
                          assembly { size := extcodesize(account) }
                          return size > 0;
                      }
                      /**
                       * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                       * `recipient`, forwarding all available gas and reverting on errors.
                       *
                       * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                       * of certain opcodes, possibly making contracts go over the 2300 gas limit
                       * imposed by `transfer`, making them unable to receive funds via
                       * `transfer`. {sendValue} removes this limitation.
                       *
                       * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                       *
                       * IMPORTANT: because control is transferred to `recipient`, care must be
                       * taken to not create reentrancy vulnerabilities. Consider using
                       * {ReentrancyGuard} or the
                       * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                       */
                      function sendValue(address payable recipient, uint256 amount) internal {
                          require(address(this).balance >= amount, "Address: insufficient balance");
                          // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                          (bool success, ) = recipient.call{ value: amount }("");
                          require(success, "Address: unable to send value, recipient may have reverted");
                      }
                      /**
                       * @dev Performs a Solidity function call using a low level `call`. A
                       * plain`call` is an unsafe replacement for a function call: use this
                       * function instead.
                       *
                       * If `target` reverts with a revert reason, it is bubbled up by this
                       * function (like regular Solidity function calls).
                       *
                       * Returns the raw returned data. To convert to the expected return value,
                       * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                       *
                       * Requirements:
                       *
                       * - `target` must be a contract.
                       * - calling `target` with `data` must not revert.
                       *
                       * _Available since v3.1._
                       */
                      function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                        return functionCall(target, data, "Address: low-level call failed");
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                       * `errorMessage` as a fallback revert reason when `target` reverts.
                       *
                       * _Available since v3.1._
                       */
                      function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                          return functionCallWithValue(target, data, 0, errorMessage);
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                       * but also transferring `value` wei to `target`.
                       *
                       * Requirements:
                       *
                       * - the calling contract must have an ETH balance of at least `value`.
                       * - the called Solidity function must be `payable`.
                       *
                       * _Available since v3.1._
                       */
                      function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                          return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                      }
                      /**
                       * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                       * with `errorMessage` as a fallback revert reason when `target` reverts.
                       *
                       * _Available since v3.1._
                       */
                      function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                          require(address(this).balance >= value, "Address: insufficient balance for call");
                          require(isContract(target), "Address: call to non-contract");
                          // solhint-disable-next-line avoid-low-level-calls
                          (bool success, bytes memory returndata) = target.call{ value: value }(data);
                          return _verifyCallResult(success, returndata, errorMessage);
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                       * but performing a static call.
                       *
                       * _Available since v3.3._
                       */
                      function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                          return functionStaticCall(target, data, "Address: low-level static call failed");
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                       * but performing a static call.
                       *
                       * _Available since v3.3._
                       */
                      function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                          require(isContract(target), "Address: static call to non-contract");
                          // solhint-disable-next-line avoid-low-level-calls
                          (bool success, bytes memory returndata) = target.staticcall(data);
                          return _verifyCallResult(success, returndata, errorMessage);
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                       * but performing a delegate call.
                       *
                       * _Available since v3.4._
                       */
                      function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                          return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                      }
                      /**
                       * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                       * but performing a delegate call.
                       *
                       * _Available since v3.4._
                       */
                      function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                          require(isContract(target), "Address: delegate call to non-contract");
                          // solhint-disable-next-line avoid-low-level-calls
                          (bool success, bytes memory returndata) = target.delegatecall(data);
                          return _verifyCallResult(success, returndata, errorMessage);
                      }
                      function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                          if (success) {
                              return returndata;
                          } else {
                              // Look for revert reason and bubble it up if present
                              if (returndata.length > 0) {
                                  // The easiest way to bubble the revert reason is using memory via assembly
                                  // solhint-disable-next-line no-inline-assembly
                                  assembly {
                                      let returndata_size := mload(returndata)
                                      revert(add(32, returndata), returndata_size)
                                  }
                              } else {
                                  revert(errorMessage);
                              }
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity >=0.6.0 <0.8.0;
                  import "./IERC20.sol";
                  import "../../math/SafeMath.sol";
                  import "../../utils/Address.sol";
                  /**
                   * @title SafeERC20
                   * @dev Wrappers around ERC20 operations that throw on failure (when the token
                   * contract returns false). Tokens that return no value (and instead revert or
                   * throw on failure) are also supported, non-reverting calls are assumed to be
                   * successful.
                   * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
                   * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
                   */
                  library SafeERC20 {
                      using SafeMath for uint256;
                      using Address for address;
                      function safeTransfer(IERC20 token, address to, uint256 value) internal {
                          _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
                      }
                      function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
                          _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
                      }
                      /**
                       * @dev Deprecated. This function has issues similar to the ones found in
                       * {IERC20-approve}, and its usage is discouraged.
                       *
                       * Whenever possible, use {safeIncreaseAllowance} and
                       * {safeDecreaseAllowance} instead.
                       */
                      function safeApprove(IERC20 token, address spender, uint256 value) internal {
                          // safeApprove should only be called when setting an initial allowance,
                          // or when resetting it to zero. To increase and decrease it, use
                          // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                          // solhint-disable-next-line max-line-length
                          require((value == 0) || (token.allowance(address(this), spender) == 0),
                              "SafeERC20: approve from non-zero to non-zero allowance"
                          );
                          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
                      }
                      function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                          uint256 newAllowance = token.allowance(address(this), spender).add(value);
                          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                      }
                      function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                          uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
                          _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                      }
                      /**
                       * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
                       * on the return value: the return value is optional (but if data is returned, it must not be false).
                       * @param token The token targeted by the call.
                       * @param data The call data (encoded using abi.encode or one of its variants).
                       */
                      function _callOptionalReturn(IERC20 token, bytes memory data) private {
                          // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                          // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
                          // the target address contains contract code and also asserts for success in the low-level call.
                          bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
                          if (returndata.length > 0) { // Return data is optional
                              // solhint-disable-next-line max-line-length
                              require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity >=0.6.0 <0.8.0;
                  /**
                   * @dev Interface of the ERC20 standard as defined in the EIP.
                   */
                  interface IERC20 {
                      /**
                       * @dev Returns the amount of tokens in existence.
                       */
                      function totalSupply() external view returns (uint256);
                      /**
                       * @dev Returns the amount of tokens owned by `account`.
                       */
                      function balanceOf(address account) external view returns (uint256);
                      /**
                       * @dev Moves `amount` tokens from the caller's account to `recipient`.
                       *
                       * Returns a boolean value indicating whether the operation succeeded.
                       *
                       * Emits a {Transfer} event.
                       */
                      function transfer(address recipient, uint256 amount) external returns (bool);
                      /**
                       * @dev Returns the remaining number of tokens that `spender` will be
                       * allowed to spend on behalf of `owner` through {transferFrom}. This is
                       * zero by default.
                       *
                       * This value changes when {approve} or {transferFrom} are called.
                       */
                      function allowance(address owner, address spender) external view returns (uint256);
                      /**
                       * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                       *
                       * Returns a boolean value indicating whether the operation succeeded.
                       *
                       * IMPORTANT: Beware that changing an allowance with this method brings the risk
                       * that someone may use both the old and the new allowance by unfortunate
                       * transaction ordering. One possible solution to mitigate this race
                       * condition is to first reduce the spender's allowance to 0 and set the
                       * desired value afterwards:
                       * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                       *
                       * Emits an {Approval} event.
                       */
                      function approve(address spender, uint256 amount) external returns (bool);
                      /**
                       * @dev Moves `amount` tokens from `sender` to `recipient` using the
                       * allowance mechanism. `amount` is then deducted from the caller's
                       * allowance.
                       *
                       * Returns a boolean value indicating whether the operation succeeded.
                       *
                       * Emits a {Transfer} event.
                       */
                      function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                      /**
                       * @dev Emitted when `value` tokens are moved from one account (`from`) to
                       * another (`to`).
                       *
                       * Note that `value` may be zero.
                       */
                      event Transfer(address indexed from, address indexed to, uint256 value);
                      /**
                       * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                       * a call to {approve}. `value` is the new allowance.
                       */
                      event Approval(address indexed owner, address indexed spender, uint256 value);
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity >=0.6.0 <0.8.0;
                  /**
                   * @dev Wrappers over Solidity's arithmetic operations with added overflow
                   * checks.
                   *
                   * Arithmetic operations in Solidity wrap on overflow. This can easily result
                   * in bugs, because programmers usually assume that an overflow raises an
                   * error, which is the standard behavior in high level programming languages.
                   * `SafeMath` restores this intuition by reverting the transaction when an
                   * operation overflows.
                   *
                   * Using this library instead of the unchecked operations eliminates an entire
                   * class of bugs, so it's recommended to use it always.
                   */
                  library SafeMath {
                      /**
                       * @dev Returns the addition of two unsigned integers, with an overflow flag.
                       *
                       * _Available since v3.4._
                       */
                      function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                          uint256 c = a + b;
                          if (c < a) return (false, 0);
                          return (true, c);
                      }
                      /**
                       * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                       *
                       * _Available since v3.4._
                       */
                      function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                          if (b > a) return (false, 0);
                          return (true, a - b);
                      }
                      /**
                       * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                       *
                       * _Available since v3.4._
                       */
                      function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                          // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                          // benefit is lost if 'b' is also tested.
                          // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                          if (a == 0) return (true, 0);
                          uint256 c = a * b;
                          if (c / a != b) return (false, 0);
                          return (true, c);
                      }
                      /**
                       * @dev Returns the division of two unsigned integers, with a division by zero flag.
                       *
                       * _Available since v3.4._
                       */
                      function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                          if (b == 0) return (false, 0);
                          return (true, a / b);
                      }
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                       *
                       * _Available since v3.4._
                       */
                      function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                          if (b == 0) return (false, 0);
                          return (true, a % b);
                      }
                      /**
                       * @dev Returns the addition of two unsigned integers, reverting on
                       * overflow.
                       *
                       * Counterpart to Solidity's `+` operator.
                       *
                       * Requirements:
                       *
                       * - Addition cannot overflow.
                       */
                      function add(uint256 a, uint256 b) internal pure returns (uint256) {
                          uint256 c = a + b;
                          require(c >= a, "SafeMath: addition overflow");
                          return c;
                      }
                      /**
                       * @dev Returns the subtraction of two unsigned integers, reverting on
                       * overflow (when the result is negative).
                       *
                       * Counterpart to Solidity's `-` operator.
                       *
                       * Requirements:
                       *
                       * - Subtraction cannot overflow.
                       */
                      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                          require(b <= a, "SafeMath: subtraction overflow");
                          return a - b;
                      }
                      /**
                       * @dev Returns the multiplication of two unsigned integers, reverting on
                       * overflow.
                       *
                       * Counterpart to Solidity's `*` operator.
                       *
                       * Requirements:
                       *
                       * - Multiplication cannot overflow.
                       */
                      function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                          if (a == 0) return 0;
                          uint256 c = a * b;
                          require(c / a == b, "SafeMath: multiplication overflow");
                          return c;
                      }
                      /**
                       * @dev Returns the integer division of two unsigned integers, reverting on
                       * division by zero. The result is rounded towards zero.
                       *
                       * Counterpart to Solidity's `/` operator. Note: this function uses a
                       * `revert` opcode (which leaves remaining gas untouched) while Solidity
                       * uses an invalid opcode to revert (consuming all remaining gas).
                       *
                       * Requirements:
                       *
                       * - The divisor cannot be zero.
                       */
                      function div(uint256 a, uint256 b) internal pure returns (uint256) {
                          require(b > 0, "SafeMath: division by zero");
                          return a / b;
                      }
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * reverting when dividing by zero.
                       *
                       * Counterpart to Solidity's `%` operator. This function uses a `revert`
                       * opcode (which leaves remaining gas untouched) while Solidity uses an
                       * invalid opcode to revert (consuming all remaining gas).
                       *
                       * Requirements:
                       *
                       * - The divisor cannot be zero.
                       */
                      function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                          require(b > 0, "SafeMath: modulo by zero");
                          return a % b;
                      }
                      /**
                       * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                       * overflow (when the result is negative).
                       *
                       * CAUTION: This function is deprecated because it requires allocating memory for the error
                       * message unnecessarily. For custom revert reasons use {trySub}.
                       *
                       * Counterpart to Solidity's `-` operator.
                       *
                       * Requirements:
                       *
                       * - Subtraction cannot overflow.
                       */
                      function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                          require(b <= a, errorMessage);
                          return a - b;
                      }
                      /**
                       * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                       * division by zero. The result is rounded towards zero.
                       *
                       * CAUTION: This function is deprecated because it requires allocating memory for the error
                       * message unnecessarily. For custom revert reasons use {tryDiv}.
                       *
                       * Counterpart to Solidity's `/` operator. Note: this function uses a
                       * `revert` opcode (which leaves remaining gas untouched) while Solidity
                       * uses an invalid opcode to revert (consuming all remaining gas).
                       *
                       * Requirements:
                       *
                       * - The divisor cannot be zero.
                       */
                      function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                          require(b > 0, errorMessage);
                          return a / b;
                      }
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * reverting with custom message when dividing by zero.
                       *
                       * CAUTION: This function is deprecated because it requires allocating memory for the error
                       * message unnecessarily. For custom revert reasons use {tryMod}.
                       *
                       * Counterpart to Solidity's `%` operator. This function uses a `revert`
                       * opcode (which leaves remaining gas untouched) while Solidity uses an
                       * invalid opcode to revert (consuming all remaining gas).
                       *
                       * Requirements:
                       *
                       * - The divisor cannot be zero.
                       */
                      function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                          require(b > 0, errorMessage);
                          return a % b;
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { FiatTokenV2 } from "./FiatTokenV2.sol";
                  // solhint-disable func-name-mixedcase
                  /**
                   * @title FiatToken V2.1
                   * @notice ERC20 Token backed by fiat reserves, version 2.1
                   */
                  contract FiatTokenV2_1 is FiatTokenV2 {
                      /**
                       * @notice Initialize v2.1
                       * @param lostAndFound  The address to which the locked funds are sent
                       */
                      function initializeV2_1(address lostAndFound) external {
                          // solhint-disable-next-line reason-string
                          require(_initializedVersion == 1);
                          uint256 lockedAmount = _balanceOf(address(this));
                          if (lockedAmount > 0) {
                              _transfer(address(this), lostAndFound, lockedAmount);
                          }
                          _blacklist(address(this));
                          _initializedVersion = 2;
                      }
                      /**
                       * @notice Version string for the EIP712 domain separator
                       * @return Version string
                       */
                      function version() external pure returns (string memory) {
                          return "2";
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { FiatTokenV1_1 } from "../v1.1/FiatTokenV1_1.sol";
                  import { EIP712 } from "../util/EIP712.sol";
                  import { EIP3009 } from "./EIP3009.sol";
                  import { EIP2612 } from "./EIP2612.sol";
                  /**
                   * @title FiatToken V2
                   * @notice ERC20 Token backed by fiat reserves, version 2
                   */
                  contract FiatTokenV2 is FiatTokenV1_1, EIP3009, EIP2612 {
                      uint8 internal _initializedVersion;
                      /**
                       * @notice Initialize v2
                       * @param newName   New token name
                       */
                      function initializeV2(string calldata newName) external {
                          // solhint-disable-next-line reason-string
                          require(initialized && _initializedVersion == 0);
                          name = newName;
                          _DEPRECATED_CACHED_DOMAIN_SEPARATOR = EIP712.makeDomainSeparator(
                              newName,
                              "2"
                          );
                          _initializedVersion = 1;
                      }
                      /**
                       * @notice Increase the allowance by a given increment
                       * @param spender   Spender's address
                       * @param increment Amount of increase in allowance
                       * @return True if successful
                       */
                      function increaseAllowance(address spender, uint256 increment)
                          external
                          virtual
                          whenNotPaused
                          notBlacklisted(msg.sender)
                          notBlacklisted(spender)
                          returns (bool)
                      {
                          _increaseAllowance(msg.sender, spender, increment);
                          return true;
                      }
                      /**
                       * @notice Decrease the allowance by a given decrement
                       * @param spender   Spender's address
                       * @param decrement Amount of decrease in allowance
                       * @return True if successful
                       */
                      function decreaseAllowance(address spender, uint256 decrement)
                          external
                          virtual
                          whenNotPaused
                          notBlacklisted(msg.sender)
                          notBlacklisted(spender)
                          returns (bool)
                      {
                          _decreaseAllowance(msg.sender, spender, decrement);
                          return true;
                      }
                      /**
                       * @notice Execute a transfer with a signed authorization
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function transferWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                          _transferWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              v,
                              r,
                              s
                          );
                      }
                      /**
                       * @notice Receive a transfer with a signed authorization from the payer
                       * @dev This has an additional check to ensure that the payee's address
                       * matches the caller of this function to prevent front-running attacks.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function receiveWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external whenNotPaused notBlacklisted(from) notBlacklisted(to) {
                          _receiveWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              v,
                              r,
                              s
                          );
                      }
                      /**
                       * @notice Attempt to cancel an authorization
                       * @dev Works only if the authorization is not yet used.
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function cancelAuthorization(
                          address authorizer,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external whenNotPaused {
                          _cancelAuthorization(authorizer, nonce, v, r, s);
                      }
                      /**
                       * @notice Update allowance with a signed permit
                       * @param owner       Token owner's address (Authorizer)
                       * @param spender     Spender's address
                       * @param value       Amount of allowance
                       * @param deadline    The time at which the signature expires (unix time), or max uint256 value to signal no expiration
                       * @param v           v of the signature
                       * @param r           r of the signature
                       * @param s           s of the signature
                       */
                      function permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      )
                          external
                          virtual
                          whenNotPaused
                          notBlacklisted(owner)
                          notBlacklisted(spender)
                      {
                          _permit(owner, spender, value, deadline, v, r, s);
                      }
                      /**
                       * @dev Internal function to increase the allowance by a given increment
                       * @param owner     Token owner's address
                       * @param spender   Spender's address
                       * @param increment Amount of increase
                       */
                      function _increaseAllowance(
                          address owner,
                          address spender,
                          uint256 increment
                      ) internal override {
                          _approve(owner, spender, allowed[owner][spender].add(increment));
                      }
                      /**
                       * @dev Internal function to decrease the allowance by a given decrement
                       * @param owner     Token owner's address
                       * @param spender   Spender's address
                       * @param decrement Amount of decrease
                       */
                      function _decreaseAllowance(
                          address owner,
                          address spender,
                          uint256 decrement
                      ) internal override {
                          _approve(
                              owner,
                              spender,
                              allowed[owner][spender].sub(
                                  decrement,
                                  "ERC20: decreased allowance below zero"
                              )
                          );
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  // solhint-disable func-name-mixedcase
                  /**
                   * @title EIP712 Domain
                   */
                  contract EIP712Domain {
                      // was originally DOMAIN_SEPARATOR
                      // but that has been moved to a method so we can override it in V2_2+
                      bytes32 internal _DEPRECATED_CACHED_DOMAIN_SEPARATOR;
                      /**
                       * @notice Get the EIP712 Domain Separator.
                       * @return The bytes32 EIP712 domain separator.
                       */
                      function DOMAIN_SEPARATOR() external view returns (bytes32) {
                          return _domainSeparator();
                      }
                      /**
                       * @dev Internal method to get the EIP712 Domain Separator.
                       * @return The bytes32 EIP712 domain separator.
                       */
                      function _domainSeparator() internal virtual view returns (bytes32) {
                          return _DEPRECATED_CACHED_DOMAIN_SEPARATOR;
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { AbstractFiatTokenV2 } from "./AbstractFiatTokenV2.sol";
                  import { EIP712Domain } from "./EIP712Domain.sol";
                  import { SignatureChecker } from "../util/SignatureChecker.sol";
                  import { MessageHashUtils } from "../util/MessageHashUtils.sol";
                  /**
                   * @title EIP-3009
                   * @notice Provide internal implementation for gas-abstracted transfers
                   * @dev Contracts that inherit from this must wrap these with publicly
                   * accessible functions, optionally adding modifiers where necessary
                   */
                  abstract contract EIP3009 is AbstractFiatTokenV2, EIP712Domain {
                      // keccak256("TransferWithAuthorization(address from,address to,uint256 value,uint256 validAfter,uint256 validBefore,bytes32 nonce)")
                      bytes32
                          public constant TRANSFER_WITH_AUTHORIZATION_TYPEHASH = 0x7c7c6cdb67a18743f49ec6fa9b35f50d52ed05cbed4cc592e13b44501c1a2267;
                      // keccak256("ReceiveWithAuthorization(address from,address to,uint256 value,uint256 validAfter,uint256 validBefore,bytes32 nonce)")
                      bytes32
                          public constant RECEIVE_WITH_AUTHORIZATION_TYPEHASH = 0xd099cc98ef71107a616c4f0f941f04c322d8e254fe26b3c6668db87aae413de8;
                      // keccak256("CancelAuthorization(address authorizer,bytes32 nonce)")
                      bytes32
                          public constant CANCEL_AUTHORIZATION_TYPEHASH = 0x158b0a9edf7a828aad02f63cd515c68ef2f50ba807396f6d12842833a1597429;
                      /**
                       * @dev authorizer address => nonce => bool (true if nonce is used)
                       */
                      mapping(address => mapping(bytes32 => bool)) private _authorizationStates;
                      event AuthorizationUsed(address indexed authorizer, bytes32 indexed nonce);
                      event AuthorizationCanceled(
                          address indexed authorizer,
                          bytes32 indexed nonce
                      );
                      /**
                       * @notice Returns the state of an authorization
                       * @dev Nonces are randomly generated 32-byte data unique to the
                       * authorizer's address
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @return True if the nonce is used
                       */
                      function authorizationState(address authorizer, bytes32 nonce)
                          external
                          view
                          returns (bool)
                      {
                          return _authorizationStates[authorizer][nonce];
                      }
                      /**
                       * @notice Execute a transfer with a signed authorization
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function _transferWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) internal {
                          _transferWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              abi.encodePacked(r, s, v)
                          );
                      }
                      /**
                       * @notice Execute a transfer with a signed authorization
                       * @dev EOA wallet signatures should be packed in the order of r, s, v.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param signature     Signature byte array produced by an EOA wallet or a contract wallet
                       */
                      function _transferWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          bytes memory signature
                      ) internal {
                          _requireValidAuthorization(from, nonce, validAfter, validBefore);
                          _requireValidSignature(
                              from,
                              keccak256(
                                  abi.encode(
                                      TRANSFER_WITH_AUTHORIZATION_TYPEHASH,
                                      from,
                                      to,
                                      value,
                                      validAfter,
                                      validBefore,
                                      nonce
                                  )
                              ),
                              signature
                          );
                          _markAuthorizationAsUsed(from, nonce);
                          _transfer(from, to, value);
                      }
                      /**
                       * @notice Receive a transfer with a signed authorization from the payer
                       * @dev This has an additional check to ensure that the payee's address
                       * matches the caller of this function to prevent front-running attacks.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function _receiveWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) internal {
                          _receiveWithAuthorization(
                              from,
                              to,
                              value,
                              validAfter,
                              validBefore,
                              nonce,
                              abi.encodePacked(r, s, v)
                          );
                      }
                      /**
                       * @notice Receive a transfer with a signed authorization from the payer
                       * @dev This has an additional check to ensure that the payee's address
                       * matches the caller of this function to prevent front-running attacks.
                       * EOA wallet signatures should be packed in the order of r, s, v.
                       * @param from          Payer's address (Authorizer)
                       * @param to            Payee's address
                       * @param value         Amount to be transferred
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       * @param nonce         Unique nonce
                       * @param signature     Signature byte array produced by an EOA wallet or a contract wallet
                       */
                      function _receiveWithAuthorization(
                          address from,
                          address to,
                          uint256 value,
                          uint256 validAfter,
                          uint256 validBefore,
                          bytes32 nonce,
                          bytes memory signature
                      ) internal {
                          require(to == msg.sender, "FiatTokenV2: caller must be the payee");
                          _requireValidAuthorization(from, nonce, validAfter, validBefore);
                          _requireValidSignature(
                              from,
                              keccak256(
                                  abi.encode(
                                      RECEIVE_WITH_AUTHORIZATION_TYPEHASH,
                                      from,
                                      to,
                                      value,
                                      validAfter,
                                      validBefore,
                                      nonce
                                  )
                              ),
                              signature
                          );
                          _markAuthorizationAsUsed(from, nonce);
                          _transfer(from, to, value);
                      }
                      /**
                       * @notice Attempt to cancel an authorization
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @param v             v of the signature
                       * @param r             r of the signature
                       * @param s             s of the signature
                       */
                      function _cancelAuthorization(
                          address authorizer,
                          bytes32 nonce,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) internal {
                          _cancelAuthorization(authorizer, nonce, abi.encodePacked(r, s, v));
                      }
                      /**
                       * @notice Attempt to cancel an authorization
                       * @dev EOA wallet signatures should be packed in the order of r, s, v.
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @param signature     Signature byte array produced by an EOA wallet or a contract wallet
                       */
                      function _cancelAuthorization(
                          address authorizer,
                          bytes32 nonce,
                          bytes memory signature
                      ) internal {
                          _requireUnusedAuthorization(authorizer, nonce);
                          _requireValidSignature(
                              authorizer,
                              keccak256(
                                  abi.encode(CANCEL_AUTHORIZATION_TYPEHASH, authorizer, nonce)
                              ),
                              signature
                          );
                          _authorizationStates[authorizer][nonce] = true;
                          emit AuthorizationCanceled(authorizer, nonce);
                      }
                      /**
                       * @notice Validates that signature against input data struct
                       * @param signer        Signer's address
                       * @param dataHash      Hash of encoded data struct
                       * @param signature     Signature byte array produced by an EOA wallet or a contract wallet
                       */
                      function _requireValidSignature(
                          address signer,
                          bytes32 dataHash,
                          bytes memory signature
                      ) private view {
                          require(
                              SignatureChecker.isValidSignatureNow(
                                  signer,
                                  MessageHashUtils.toTypedDataHash(_domainSeparator(), dataHash),
                                  signature
                              ),
                              "FiatTokenV2: invalid signature"
                          );
                      }
                      /**
                       * @notice Check that an authorization is unused
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       */
                      function _requireUnusedAuthorization(address authorizer, bytes32 nonce)
                          private
                          view
                      {
                          require(
                              !_authorizationStates[authorizer][nonce],
                              "FiatTokenV2: authorization is used or canceled"
                          );
                      }
                      /**
                       * @notice Check that authorization is valid
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       * @param validAfter    The time after which this is valid (unix time)
                       * @param validBefore   The time before which this is valid (unix time)
                       */
                      function _requireValidAuthorization(
                          address authorizer,
                          bytes32 nonce,
                          uint256 validAfter,
                          uint256 validBefore
                      ) private view {
                          require(
                              now > validAfter,
                              "FiatTokenV2: authorization is not yet valid"
                          );
                          require(now < validBefore, "FiatTokenV2: authorization is expired");
                          _requireUnusedAuthorization(authorizer, nonce);
                      }
                      /**
                       * @notice Mark an authorization as used
                       * @param authorizer    Authorizer's address
                       * @param nonce         Nonce of the authorization
                       */
                      function _markAuthorizationAsUsed(address authorizer, bytes32 nonce)
                          private
                      {
                          _authorizationStates[authorizer][nonce] = true;
                          emit AuthorizationUsed(authorizer, nonce);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { AbstractFiatTokenV2 } from "./AbstractFiatTokenV2.sol";
                  import { EIP712Domain } from "./EIP712Domain.sol";
                  import { MessageHashUtils } from "../util/MessageHashUtils.sol";
                  import { SignatureChecker } from "../util/SignatureChecker.sol";
                  /**
                   * @title EIP-2612
                   * @notice Provide internal implementation for gas-abstracted approvals
                   */
                  abstract contract EIP2612 is AbstractFiatTokenV2, EIP712Domain {
                      // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)")
                      bytes32
                          public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
                      mapping(address => uint256) private _permitNonces;
                      /**
                       * @notice Nonces for permit
                       * @param owner Token owner's address (Authorizer)
                       * @return Next nonce
                       */
                      function nonces(address owner) external view returns (uint256) {
                          return _permitNonces[owner];
                      }
                      /**
                       * @notice Verify a signed approval permit and execute if valid
                       * @param owner     Token owner's address (Authorizer)
                       * @param spender   Spender's address
                       * @param value     Amount of allowance
                       * @param deadline  The time at which the signature expires (unix time), or max uint256 value to signal no expiration
                       * @param v         v of the signature
                       * @param r         r of the signature
                       * @param s         s of the signature
                       */
                      function _permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) internal {
                          _permit(owner, spender, value, deadline, abi.encodePacked(r, s, v));
                      }
                      /**
                       * @notice Verify a signed approval permit and execute if valid
                       * @dev EOA wallet signatures should be packed in the order of r, s, v.
                       * @param owner      Token owner's address (Authorizer)
                       * @param spender    Spender's address
                       * @param value      Amount of allowance
                       * @param deadline   The time at which the signature expires (unix time), or max uint256 value to signal no expiration
                       * @param signature  Signature byte array signed by an EOA wallet or a contract wallet
                       */
                      function _permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          bytes memory signature
                      ) internal {
                          require(
                              deadline == type(uint256).max || deadline >= now,
                              "FiatTokenV2: permit is expired"
                          );
                          bytes32 typedDataHash = MessageHashUtils.toTypedDataHash(
                              _domainSeparator(),
                              keccak256(
                                  abi.encode(
                                      PERMIT_TYPEHASH,
                                      owner,
                                      spender,
                                      value,
                                      _permitNonces[owner]++,
                                      deadline
                                  )
                              )
                          );
                          require(
                              SignatureChecker.isValidSignatureNow(
                                  owner,
                                  typedDataHash,
                                  signature
                              ),
                              "EIP2612: invalid signature"
                          );
                          _approve(owner, spender, value);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { AbstractFiatTokenV1 } from "../v1/AbstractFiatTokenV1.sol";
                  abstract contract AbstractFiatTokenV2 is AbstractFiatTokenV1 {
                      function _increaseAllowance(
                          address owner,
                          address spender,
                          uint256 increment
                      ) internal virtual;
                      function _decreaseAllowance(
                          address owner,
                          address spender,
                          uint256 decrement
                      ) internal virtual;
                  }
                  /**
                   * SPDX-License-Identifier: MIT
                   *
                   * Copyright (c) 2016 Smart Contract Solutions, Inc.
                   * Copyright (c) 2018-2020 CENTRE SECZ
                   *
                   * Permission is hereby granted, free of charge, to any person obtaining a copy
                   * of this software and associated documentation files (the "Software"), to deal
                   * in the Software without restriction, including without limitation the rights
                   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                   * copies of the Software, and to permit persons to whom the Software is
                   * furnished to do so, subject to the following conditions:
                   *
                   * The above copyright notice and this permission notice shall be included in
                   * copies or substantial portions of the Software.
                   *
                   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                   * SOFTWARE.
                   */
                  pragma solidity 0.6.12;
                  import { Ownable } from "./Ownable.sol";
                  /**
                   * @notice Base contract which allows children to implement an emergency stop
                   * mechanism
                   * @dev Forked from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/feb665136c0dae9912e08397c1a21c4af3651ef3/contracts/lifecycle/Pausable.sol
                   * Modifications:
                   * 1. Added pauser role, switched pause/unpause to be onlyPauser (6/14/2018)
                   * 2. Removed whenNotPause/whenPaused from pause/unpause (6/14/2018)
                   * 3. Removed whenPaused (6/14/2018)
                   * 4. Switches ownable library to use ZeppelinOS (7/12/18)
                   * 5. Remove constructor (7/13/18)
                   * 6. Reformat, conform to Solidity 0.6 syntax and add error messages (5/13/20)
                   * 7. Make public functions external (5/27/20)
                   */
                  contract Pausable is Ownable {
                      event Pause();
                      event Unpause();
                      event PauserChanged(address indexed newAddress);
                      address public pauser;
                      bool public paused = false;
                      /**
                       * @dev Modifier to make a function callable only when the contract is not paused.
                       */
                      modifier whenNotPaused() {
                          require(!paused, "Pausable: paused");
                          _;
                      }
                      /**
                       * @dev throws if called by any account other than the pauser
                       */
                      modifier onlyPauser() {
                          require(msg.sender == pauser, "Pausable: caller is not the pauser");
                          _;
                      }
                      /**
                       * @dev called by the owner to pause, triggers stopped state
                       */
                      function pause() external onlyPauser {
                          paused = true;
                          emit Pause();
                      }
                      /**
                       * @dev called by the owner to unpause, returns to normal state
                       */
                      function unpause() external onlyPauser {
                          paused = false;
                          emit Unpause();
                      }
                      /**
                       * @notice Updates the pauser address.
                       * @param _newPauser The address of the new pauser.
                       */
                      function updatePauser(address _newPauser) external onlyOwner {
                          require(
                              _newPauser != address(0),
                              "Pausable: new pauser is the zero address"
                          );
                          pauser = _newPauser;
                          emit PauserChanged(pauser);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: MIT
                   *
                   * Copyright (c) 2018 zOS Global Limited.
                   * Copyright (c) 2018-2020 CENTRE SECZ
                   *
                   * Permission is hereby granted, free of charge, to any person obtaining a copy
                   * of this software and associated documentation files (the "Software"), to deal
                   * in the Software without restriction, including without limitation the rights
                   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
                   * copies of the Software, and to permit persons to whom the Software is
                   * furnished to do so, subject to the following conditions:
                   *
                   * The above copyright notice and this permission notice shall be included in
                   * copies or substantial portions of the Software.
                   *
                   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
                   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
                   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
                   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
                   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
                   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
                   * SOFTWARE.
                   */
                  pragma solidity 0.6.12;
                  /**
                   * @notice The Ownable contract has an owner address, and provides basic
                   * authorization control functions
                   * @dev Forked from https://github.com/OpenZeppelin/openzeppelin-labs/blob/3887ab77b8adafba4a26ace002f3a684c1a3388b/upgradeability_ownership/contracts/ownership/Ownable.sol
                   * Modifications:
                   * 1. Consolidate OwnableStorage into this contract (7/13/18)
                   * 2. Reformat, conform to Solidity 0.6 syntax, and add error messages (5/13/20)
                   * 3. Make public functions external (5/27/20)
                   */
                  contract Ownable {
                      // Owner of the contract
                      address private _owner;
                      /**
                       * @dev Event to show ownership has been transferred
                       * @param previousOwner representing the address of the previous owner
                       * @param newOwner representing the address of the new owner
                       */
                      event OwnershipTransferred(address previousOwner, address newOwner);
                      /**
                       * @dev The constructor sets the original owner of the contract to the sender account.
                       */
                      constructor() public {
                          setOwner(msg.sender);
                      }
                      /**
                       * @dev Tells the address of the owner
                       * @return the address of the owner
                       */
                      function owner() external view returns (address) {
                          return _owner;
                      }
                      /**
                       * @dev Sets a new owner address
                       */
                      function setOwner(address newOwner) internal {
                          _owner = newOwner;
                      }
                      /**
                       * @dev Throws if called by any account other than the owner.
                       */
                      modifier onlyOwner() {
                          require(msg.sender == _owner, "Ownable: caller is not the owner");
                          _;
                      }
                      /**
                       * @dev Allows the current owner to transfer control of the contract to a newOwner.
                       * @param newOwner The address to transfer ownership to.
                       */
                      function transferOwnership(address newOwner) external onlyOwner {
                          require(
                              newOwner != address(0),
                              "Ownable: new owner is the zero address"
                          );
                          emit OwnershipTransferred(_owner, newOwner);
                          setOwner(newOwner);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
                  import { AbstractFiatTokenV1 } from "./AbstractFiatTokenV1.sol";
                  import { Ownable } from "./Ownable.sol";
                  import { Pausable } from "./Pausable.sol";
                  import { Blacklistable } from "./Blacklistable.sol";
                  /**
                   * @title FiatToken
                   * @dev ERC20 Token backed by fiat reserves
                   */
                  contract FiatTokenV1 is AbstractFiatTokenV1, Ownable, Pausable, Blacklistable {
                      using SafeMath for uint256;
                      string public name;
                      string public symbol;
                      uint8 public decimals;
                      string public currency;
                      address public masterMinter;
                      bool internal initialized;
                      /// @dev A mapping that stores the balance and blacklist states for a given address.
                      /// The first bit defines whether the address is blacklisted (1 if blacklisted, 0 otherwise).
                      /// The last 255 bits define the balance for the address.
                      mapping(address => uint256) internal balanceAndBlacklistStates;
                      mapping(address => mapping(address => uint256)) internal allowed;
                      uint256 internal totalSupply_ = 0;
                      mapping(address => bool) internal minters;
                      mapping(address => uint256) internal minterAllowed;
                      event Mint(address indexed minter, address indexed to, uint256 amount);
                      event Burn(address indexed burner, uint256 amount);
                      event MinterConfigured(address indexed minter, uint256 minterAllowedAmount);
                      event MinterRemoved(address indexed oldMinter);
                      event MasterMinterChanged(address indexed newMasterMinter);
                      /**
                       * @notice Initializes the fiat token contract.
                       * @param tokenName       The name of the fiat token.
                       * @param tokenSymbol     The symbol of the fiat token.
                       * @param tokenCurrency   The fiat currency that the token represents.
                       * @param tokenDecimals   The number of decimals that the token uses.
                       * @param newMasterMinter The masterMinter address for the fiat token.
                       * @param newPauser       The pauser address for the fiat token.
                       * @param newBlacklister  The blacklister address for the fiat token.
                       * @param newOwner        The owner of the fiat token.
                       */
                      function initialize(
                          string memory tokenName,
                          string memory tokenSymbol,
                          string memory tokenCurrency,
                          uint8 tokenDecimals,
                          address newMasterMinter,
                          address newPauser,
                          address newBlacklister,
                          address newOwner
                      ) public {
                          require(!initialized, "FiatToken: contract is already initialized");
                          require(
                              newMasterMinter != address(0),
                              "FiatToken: new masterMinter is the zero address"
                          );
                          require(
                              newPauser != address(0),
                              "FiatToken: new pauser is the zero address"
                          );
                          require(
                              newBlacklister != address(0),
                              "FiatToken: new blacklister is the zero address"
                          );
                          require(
                              newOwner != address(0),
                              "FiatToken: new owner is the zero address"
                          );
                          name = tokenName;
                          symbol = tokenSymbol;
                          currency = tokenCurrency;
                          decimals = tokenDecimals;
                          masterMinter = newMasterMinter;
                          pauser = newPauser;
                          blacklister = newBlacklister;
                          setOwner(newOwner);
                          initialized = true;
                      }
                      /**
                       * @dev Throws if called by any account other than a minter.
                       */
                      modifier onlyMinters() {
                          require(minters[msg.sender], "FiatToken: caller is not a minter");
                          _;
                      }
                      /**
                       * @notice Mints fiat tokens to an address.
                       * @param _to The address that will receive the minted tokens.
                       * @param _amount The amount of tokens to mint. Must be less than or equal
                       * to the minterAllowance of the caller.
                       * @return True if the operation was successful.
                       */
                      function mint(address _to, uint256 _amount)
                          external
                          whenNotPaused
                          onlyMinters
                          notBlacklisted(msg.sender)
                          notBlacklisted(_to)
                          returns (bool)
                      {
                          require(_to != address(0), "FiatToken: mint to the zero address");
                          require(_amount > 0, "FiatToken: mint amount not greater than 0");
                          uint256 mintingAllowedAmount = minterAllowed[msg.sender];
                          require(
                              _amount <= mintingAllowedAmount,
                              "FiatToken: mint amount exceeds minterAllowance"
                          );
                          totalSupply_ = totalSupply_.add(_amount);
                          _setBalance(_to, _balanceOf(_to).add(_amount));
                          minterAllowed[msg.sender] = mintingAllowedAmount.sub(_amount);
                          emit Mint(msg.sender, _to, _amount);
                          emit Transfer(address(0), _to, _amount);
                          return true;
                      }
                      /**
                       * @dev Throws if called by any account other than the masterMinter
                       */
                      modifier onlyMasterMinter() {
                          require(
                              msg.sender == masterMinter,
                              "FiatToken: caller is not the masterMinter"
                          );
                          _;
                      }
                      /**
                       * @notice Gets the minter allowance for an account.
                       * @param minter The address to check.
                       * @return The remaining minter allowance for the account.
                       */
                      function minterAllowance(address minter) external view returns (uint256) {
                          return minterAllowed[minter];
                      }
                      /**
                       * @notice Checks if an account is a minter.
                       * @param account The address to check.
                       * @return True if the account is a minter, false if the account is not a minter.
                       */
                      function isMinter(address account) external view returns (bool) {
                          return minters[account];
                      }
                      /**
                       * @notice Gets the remaining amount of fiat tokens a spender is allowed to transfer on
                       * behalf of the token owner.
                       * @param owner   The token owner's address.
                       * @param spender The spender's address.
                       * @return The remaining allowance.
                       */
                      function allowance(address owner, address spender)
                          external
                          override
                          view
                          returns (uint256)
                      {
                          return allowed[owner][spender];
                      }
                      /**
                       * @notice Gets the totalSupply of the fiat token.
                       * @return The totalSupply of the fiat token.
                       */
                      function totalSupply() external override view returns (uint256) {
                          return totalSupply_;
                      }
                      /**
                       * @notice Gets the fiat token balance of an account.
                       * @param account  The address to check.
                       * @return balance The fiat token balance of the account.
                       */
                      function balanceOf(address account)
                          external
                          override
                          view
                          returns (uint256)
                      {
                          return _balanceOf(account);
                      }
                      /**
                       * @notice Sets a fiat token allowance for a spender to spend on behalf of the caller.
                       * @param spender The spender's address.
                       * @param value   The allowance amount.
                       * @return True if the operation was successful.
                       */
                      function approve(address spender, uint256 value)
                          external
                          virtual
                          override
                          whenNotPaused
                          notBlacklisted(msg.sender)
                          notBlacklisted(spender)
                          returns (bool)
                      {
                          _approve(msg.sender, spender, value);
                          return true;
                      }
                      /**
                       * @dev Internal function to set allowance.
                       * @param owner     Token owner's address.
                       * @param spender   Spender's address.
                       * @param value     Allowance amount.
                       */
                      function _approve(
                          address owner,
                          address spender,
                          uint256 value
                      ) internal override {
                          require(owner != address(0), "ERC20: approve from the zero address");
                          require(spender != address(0), "ERC20: approve to the zero address");
                          allowed[owner][spender] = value;
                          emit Approval(owner, spender, value);
                      }
                      /**
                       * @notice Transfers tokens from an address to another by spending the caller's allowance.
                       * @dev The caller must have some fiat token allowance on the payer's tokens.
                       * @param from  Payer's address.
                       * @param to    Payee's address.
                       * @param value Transfer amount.
                       * @return True if the operation was successful.
                       */
                      function transferFrom(
                          address from,
                          address to,
                          uint256 value
                      )
                          external
                          override
                          whenNotPaused
                          notBlacklisted(msg.sender)
                          notBlacklisted(from)
                          notBlacklisted(to)
                          returns (bool)
                      {
                          require(
                              value <= allowed[from][msg.sender],
                              "ERC20: transfer amount exceeds allowance"
                          );
                          _transfer(from, to, value);
                          allowed[from][msg.sender] = allowed[from][msg.sender].sub(value);
                          return true;
                      }
                      /**
                       * @notice Transfers tokens from the caller.
                       * @param to    Payee's address.
                       * @param value Transfer amount.
                       * @return True if the operation was successful.
                       */
                      function transfer(address to, uint256 value)
                          external
                          override
                          whenNotPaused
                          notBlacklisted(msg.sender)
                          notBlacklisted(to)
                          returns (bool)
                      {
                          _transfer(msg.sender, to, value);
                          return true;
                      }
                      /**
                       * @dev Internal function to process transfers.
                       * @param from  Payer's address.
                       * @param to    Payee's address.
                       * @param value Transfer amount.
                       */
                      function _transfer(
                          address from,
                          address to,
                          uint256 value
                      ) internal override {
                          require(from != address(0), "ERC20: transfer from the zero address");
                          require(to != address(0), "ERC20: transfer to the zero address");
                          require(
                              value <= _balanceOf(from),
                              "ERC20: transfer amount exceeds balance"
                          );
                          _setBalance(from, _balanceOf(from).sub(value));
                          _setBalance(to, _balanceOf(to).add(value));
                          emit Transfer(from, to, value);
                      }
                      /**
                       * @notice Adds or updates a new minter with a mint allowance.
                       * @param minter The address of the minter.
                       * @param minterAllowedAmount The minting amount allowed for the minter.
                       * @return True if the operation was successful.
                       */
                      function configureMinter(address minter, uint256 minterAllowedAmount)
                          external
                          whenNotPaused
                          onlyMasterMinter
                          returns (bool)
                      {
                          minters[minter] = true;
                          minterAllowed[minter] = minterAllowedAmount;
                          emit MinterConfigured(minter, minterAllowedAmount);
                          return true;
                      }
                      /**
                       * @notice Removes a minter.
                       * @param minter The address of the minter to remove.
                       * @return True if the operation was successful.
                       */
                      function removeMinter(address minter)
                          external
                          onlyMasterMinter
                          returns (bool)
                      {
                          minters[minter] = false;
                          minterAllowed[minter] = 0;
                          emit MinterRemoved(minter);
                          return true;
                      }
                      /**
                       * @notice Allows a minter to burn some of its own tokens.
                       * @dev The caller must be a minter, must not be blacklisted, and the amount to burn
                       * should be less than or equal to the account's balance.
                       * @param _amount the amount of tokens to be burned.
                       */
                      function burn(uint256 _amount)
                          external
                          whenNotPaused
                          onlyMinters
                          notBlacklisted(msg.sender)
                      {
                          uint256 balance = _balanceOf(msg.sender);
                          require(_amount > 0, "FiatToken: burn amount not greater than 0");
                          require(balance >= _amount, "FiatToken: burn amount exceeds balance");
                          totalSupply_ = totalSupply_.sub(_amount);
                          _setBalance(msg.sender, balance.sub(_amount));
                          emit Burn(msg.sender, _amount);
                          emit Transfer(msg.sender, address(0), _amount);
                      }
                      /**
                       * @notice Updates the master minter address.
                       * @param _newMasterMinter The address of the new master minter.
                       */
                      function updateMasterMinter(address _newMasterMinter) external onlyOwner {
                          require(
                              _newMasterMinter != address(0),
                              "FiatToken: new masterMinter is the zero address"
                          );
                          masterMinter = _newMasterMinter;
                          emit MasterMinterChanged(masterMinter);
                      }
                      /**
                       * @inheritdoc Blacklistable
                       */
                      function _blacklist(address _account) internal override {
                          _setBlacklistState(_account, true);
                      }
                      /**
                       * @inheritdoc Blacklistable
                       */
                      function _unBlacklist(address _account) internal override {
                          _setBlacklistState(_account, false);
                      }
                      /**
                       * @dev Helper method that sets the blacklist state of an account.
                       * @param _account         The address of the account.
                       * @param _shouldBlacklist True if the account should be blacklisted, false if the account should be unblacklisted.
                       */
                      function _setBlacklistState(address _account, bool _shouldBlacklist)
                          internal
                          virtual
                      {
                          _deprecatedBlacklisted[_account] = _shouldBlacklist;
                      }
                      /**
                       * @dev Helper method that sets the balance of an account.
                       * @param _account The address of the account.
                       * @param _balance The new fiat token balance of the account.
                       */
                      function _setBalance(address _account, uint256 _balance) internal virtual {
                          balanceAndBlacklistStates[_account] = _balance;
                      }
                      /**
                       * @inheritdoc Blacklistable
                       */
                      function _isBlacklisted(address _account)
                          internal
                          virtual
                          override
                          view
                          returns (bool)
                      {
                          return _deprecatedBlacklisted[_account];
                      }
                      /**
                       * @dev Helper method to obtain the balance of an account.
                       * @param _account  The address of the account.
                       * @return          The fiat token balance of the account.
                       */
                      function _balanceOf(address _account)
                          internal
                          virtual
                          view
                          returns (uint256)
                      {
                          return balanceAndBlacklistStates[_account];
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { Ownable } from "./Ownable.sol";
                  /**
                   * @title Blacklistable Token
                   * @dev Allows accounts to be blacklisted by a "blacklister" role
                   */
                  abstract contract Blacklistable is Ownable {
                      address public blacklister;
                      mapping(address => bool) internal _deprecatedBlacklisted;
                      event Blacklisted(address indexed _account);
                      event UnBlacklisted(address indexed _account);
                      event BlacklisterChanged(address indexed newBlacklister);
                      /**
                       * @dev Throws if called by any account other than the blacklister.
                       */
                      modifier onlyBlacklister() {
                          require(
                              msg.sender == blacklister,
                              "Blacklistable: caller is not the blacklister"
                          );
                          _;
                      }
                      /**
                       * @dev Throws if argument account is blacklisted.
                       * @param _account The address to check.
                       */
                      modifier notBlacklisted(address _account) {
                          require(
                              !_isBlacklisted(_account),
                              "Blacklistable: account is blacklisted"
                          );
                          _;
                      }
                      /**
                       * @notice Checks if account is blacklisted.
                       * @param _account The address to check.
                       * @return True if the account is blacklisted, false if the account is not blacklisted.
                       */
                      function isBlacklisted(address _account) external view returns (bool) {
                          return _isBlacklisted(_account);
                      }
                      /**
                       * @notice Adds account to blacklist.
                       * @param _account The address to blacklist.
                       */
                      function blacklist(address _account) external onlyBlacklister {
                          _blacklist(_account);
                          emit Blacklisted(_account);
                      }
                      /**
                       * @notice Removes account from blacklist.
                       * @param _account The address to remove from the blacklist.
                       */
                      function unBlacklist(address _account) external onlyBlacklister {
                          _unBlacklist(_account);
                          emit UnBlacklisted(_account);
                      }
                      /**
                       * @notice Updates the blacklister address.
                       * @param _newBlacklister The address of the new blacklister.
                       */
                      function updateBlacklister(address _newBlacklister) external onlyOwner {
                          require(
                              _newBlacklister != address(0),
                              "Blacklistable: new blacklister is the zero address"
                          );
                          blacklister = _newBlacklister;
                          emit BlacklisterChanged(blacklister);
                      }
                      /**
                       * @dev Checks if account is blacklisted.
                       * @param _account The address to check.
                       * @return true if the account is blacklisted, false otherwise.
                       */
                      function _isBlacklisted(address _account)
                          internal
                          virtual
                          view
                          returns (bool);
                      /**
                       * @dev Helper method that blacklists an account.
                       * @param _account The address to blacklist.
                       */
                      function _blacklist(address _account) internal virtual;
                      /**
                       * @dev Helper method that unblacklists an account.
                       * @param _account The address to unblacklist.
                       */
                      function _unBlacklist(address _account) internal virtual;
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  abstract contract AbstractFiatTokenV1 is IERC20 {
                      function _approve(
                          address owner,
                          address spender,
                          uint256 value
                      ) internal virtual;
                      function _transfer(
                          address from,
                          address to,
                          uint256 value
                      ) internal virtual;
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { Ownable } from "../v1/Ownable.sol";
                  import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  contract Rescuable is Ownable {
                      using SafeERC20 for IERC20;
                      address private _rescuer;
                      event RescuerChanged(address indexed newRescuer);
                      /**
                       * @notice Returns current rescuer
                       * @return Rescuer's address
                       */
                      function rescuer() external view returns (address) {
                          return _rescuer;
                      }
                      /**
                       * @notice Revert if called by any account other than the rescuer.
                       */
                      modifier onlyRescuer() {
                          require(msg.sender == _rescuer, "Rescuable: caller is not the rescuer");
                          _;
                      }
                      /**
                       * @notice Rescue ERC20 tokens locked up in this contract.
                       * @param tokenContract ERC20 token contract address
                       * @param to        Recipient address
                       * @param amount    Amount to withdraw
                       */
                      function rescueERC20(
                          IERC20 tokenContract,
                          address to,
                          uint256 amount
                      ) external onlyRescuer {
                          tokenContract.safeTransfer(to, amount);
                      }
                      /**
                       * @notice Updates the rescuer address.
                       * @param newRescuer The address of the new rescuer.
                       */
                      function updateRescuer(address newRescuer) external onlyOwner {
                          require(
                              newRescuer != address(0),
                              "Rescuable: new rescuer is the zero address"
                          );
                          _rescuer = newRescuer;
                          emit RescuerChanged(newRescuer);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { FiatTokenV1 } from "../v1/FiatTokenV1.sol";
                  import { Rescuable } from "./Rescuable.sol";
                  /**
                   * @title FiatTokenV1_1
                   * @dev ERC20 Token backed by fiat reserves
                   */
                  contract FiatTokenV1_1 is FiatTokenV1, Rescuable {
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  import { ECRecover } from "./ECRecover.sol";
                  import { IERC1271 } from "../interface/IERC1271.sol";
                  /**
                   * @dev Signature verification helper that can be used instead of `ECRecover.recover` to seamlessly support both ECDSA
                   * signatures from externally owned accounts (EOAs) as well as ERC1271 signatures from smart contract wallets.
                   *
                   * Adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/21bb89ef5bfc789b9333eb05e3ba2b7b284ac77c/contracts/utils/cryptography/SignatureChecker.sol
                   */
                  library SignatureChecker {
                      /**
                       * @dev Checks if a signature is valid for a given signer and data hash. If the signer is a smart contract, the
                       * signature is validated against that smart contract using ERC1271, otherwise it's validated using `ECRecover.recover`.
                       * @param signer        Address of the claimed signer
                       * @param digest        Keccak-256 hash digest of the signed message
                       * @param signature     Signature byte array associated with hash
                       */
                      function isValidSignatureNow(
                          address signer,
                          bytes32 digest,
                          bytes memory signature
                      ) external view returns (bool) {
                          if (!isContract(signer)) {
                              return ECRecover.recover(digest, signature) == signer;
                          }
                          return isValidERC1271SignatureNow(signer, digest, signature);
                      }
                      /**
                       * @dev Checks if a signature is valid for a given signer and data hash. The signature is validated
                       * against the signer smart contract using ERC1271.
                       * @param signer        Address of the claimed signer
                       * @param digest        Keccak-256 hash digest of the signed message
                       * @param signature     Signature byte array associated with hash
                       *
                       * NOTE: Unlike ECDSA signatures, contract signatures are revocable, and the outcome of this function can thus
                       * change through time. It could return true at block N and false at block N+1 (or the opposite).
                       */
                      function isValidERC1271SignatureNow(
                          address signer,
                          bytes32 digest,
                          bytes memory signature
                      ) internal view returns (bool) {
                          (bool success, bytes memory result) = signer.staticcall(
                              abi.encodeWithSelector(
                                  IERC1271.isValidSignature.selector,
                                  digest,
                                  signature
                              )
                          );
                          return (success &&
                              result.length >= 32 &&
                              abi.decode(result, (bytes32)) ==
                              bytes32(IERC1271.isValidSignature.selector));
                      }
                      /**
                       * @dev Checks if the input address is a smart contract.
                       */
                      function isContract(address addr) internal view returns (bool) {
                          uint256 size;
                          assembly {
                              size := extcodesize(addr)
                          }
                          return size > 0;
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  /**
                   * @dev Signature message hash utilities for producing digests to be consumed by {ECDSA} recovery or signing.
                   *
                   * The library provides methods for generating a hash of a message that conforms to the
                   * https://eips.ethereum.org/EIPS/eip-191[EIP 191] and https://eips.ethereum.org/EIPS/eip-712[EIP 712]
                   * specifications.
                   */
                  library MessageHashUtils {
                      /**
                       * @dev Returns the keccak256 digest of an EIP-712 typed data (EIP-191 version `0x01`).
                       * Adapted from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/21bb89ef5bfc789b9333eb05e3ba2b7b284ac77c/contracts/utils/cryptography/MessageHashUtils.sol
                       *
                       * The digest is calculated from a `domainSeparator` and a `structHash`, by prefixing them with
                       * `\\x19\\x01` and hashing the result. It corresponds to the hash signed by the
                       * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`] JSON-RPC method as part of EIP-712.
                       *
                       * @param domainSeparator    Domain separator
                       * @param structHash         Hashed EIP-712 data struct
                       * @return digest            The keccak256 digest of an EIP-712 typed data
                       */
                      function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash)
                          internal
                          pure
                          returns (bytes32 digest)
                      {
                          assembly {
                              let ptr := mload(0x40)
                              mstore(ptr, "\\x19\\x01")
                              mstore(add(ptr, 0x02), domainSeparator)
                              mstore(add(ptr, 0x22), structHash)
                              digest := keccak256(ptr, 0x42)
                          }
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  /**
                   * @title EIP712
                   * @notice A library that provides EIP712 helper functions
                   */
                  library EIP712 {
                      /**
                       * @notice Make EIP712 domain separator
                       * @param name      Contract name
                       * @param version   Contract version
                       * @param chainId   Blockchain ID
                       * @return Domain separator
                       */
                      function makeDomainSeparator(
                          string memory name,
                          string memory version,
                          uint256 chainId
                      ) internal view returns (bytes32) {
                          return
                              keccak256(
                                  abi.encode(
                                      // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)")
                                      0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f,
                                      keccak256(bytes(name)),
                                      keccak256(bytes(version)),
                                      chainId,
                                      address(this)
                                  )
                              );
                      }
                      /**
                       * @notice Make EIP712 domain separator
                       * @param name      Contract name
                       * @param version   Contract version
                       * @return Domain separator
                       */
                      function makeDomainSeparator(string memory name, string memory version)
                          internal
                          view
                          returns (bytes32)
                      {
                          uint256 chainId;
                          assembly {
                              chainId := chainid()
                          }
                          return makeDomainSeparator(name, version, chainId);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  /**
                   * @title ECRecover
                   * @notice A library that provides a safe ECDSA recovery function
                   */
                  library ECRecover {
                      /**
                       * @notice Recover signer's address from a signed message
                       * @dev Adapted from: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/65e4ffde586ec89af3b7e9140bdc9235d1254853/contracts/cryptography/ECDSA.sol
                       * Modifications: Accept v, r, and s as separate arguments
                       * @param digest    Keccak-256 hash digest of the signed message
                       * @param v         v of the signature
                       * @param r         r of the signature
                       * @param s         s of the signature
                       * @return Signer address
                       */
                      function recover(
                          bytes32 digest,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) internal pure returns (address) {
                          // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
                          // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
                          // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
                          // signatures from current libraries generate a unique signature with an s-value in the lower half order.
                          //
                          // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
                          // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
                          // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
                          // these malleable signatures as well.
                          if (
                              uint256(s) >
                              0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0
                          ) {
                              revert("ECRecover: invalid signature 's' value");
                          }
                          if (v != 27 && v != 28) {
                              revert("ECRecover: invalid signature 'v' value");
                          }
                          // If the signature is valid (and not malleable), return the signer address
                          address signer = ecrecover(digest, v, r, s);
                          require(signer != address(0), "ECRecover: invalid signature");
                          return signer;
                      }
                      /**
                       * @notice Recover signer's address from a signed message
                       * @dev Adapted from: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/0053ee040a7ff1dbc39691c9e67a69f564930a88/contracts/utils/cryptography/ECDSA.sol
                       * @param digest    Keccak-256 hash digest of the signed message
                       * @param signature Signature byte array associated with hash
                       * @return Signer address
                       */
                      function recover(bytes32 digest, bytes memory signature)
                          internal
                          pure
                          returns (address)
                      {
                          require(signature.length == 65, "ECRecover: invalid signature length");
                          bytes32 r;
                          bytes32 s;
                          uint8 v;
                          // ecrecover takes the signature parameters, and the only way to get them
                          // currently is to use assembly.
                          /// @solidity memory-safe-assembly
                          assembly {
                              r := mload(add(signature, 0x20))
                              s := mload(add(signature, 0x40))
                              v := byte(0, mload(add(signature, 0x60)))
                          }
                          return recover(digest, v, r, s);
                      }
                  }
                  /**
                   * SPDX-License-Identifier: Apache-2.0
                   *
                   * Copyright (c) 2023, Circle Internet Financial, LLC.
                   *
                   * Licensed under the Apache License, Version 2.0 (the "License");
                   * you may not use this file except in compliance with the License.
                   * You may obtain a copy of the License at
                   *
                   * http://www.apache.org/licenses/LICENSE-2.0
                   *
                   * Unless required by applicable law or agreed to in writing, software
                   * distributed under the License is distributed on an "AS IS" BASIS,
                   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                   * See the License for the specific language governing permissions and
                   * limitations under the License.
                   */
                  pragma solidity 0.6.12;
                  /**
                   * @dev Interface of the ERC1271 standard signature validation method for
                   * contracts as defined in https://eips.ethereum.org/EIPS/eip-1271[ERC-1271].
                   */
                  interface IERC1271 {
                      /**
                       * @dev Should return whether the signature provided is valid for the provided data
                       * @param hash          Hash of the data to be signed
                       * @param signature     Signature byte array associated with the provided data hash
                       * @return magicValue   bytes4 magic value 0x1626ba7e when function passes
                       */
                      function isValidSignature(bytes32 hash, bytes memory signature)
                          external
                          view
                          returns (bytes4 magicValue);
                  }