Contract Name:
ERC20Tornado
Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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;
}
/**
* @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
* `nonReentrant` function in the call stack.
*/
function _reentrancyGuardEntered() internal view returns (bool) {
return _status == _ENTERED;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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);
/**
* @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 `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../extensions/IERC20Permit.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 Address for address;
/**
* @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
/**
* @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
* calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
*/
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'
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));
}
/**
* @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 oldAllowance = token.allowance(address(this), spender);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
}
/**
* @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
}
}
/**
* @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
* 0 before setting it to a non-zero value.
*/
function forceApprove(IERC20 token, address spender, uint256 value) internal {
bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);
if (!_callOptionalReturnBool(token, approvalCall)) {
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
_callOptionalReturn(token, approvalCall);
}
}
/**
* @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
* Revert on invalid signature.
*/
function safePermit(
IERC20Permit token,
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) internal {
uint256 nonceBefore = token.nonces(owner);
token.permit(owner, spender, value, deadline, v, r, s);
uint256 nonceAfter = token.nonces(owner);
require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
}
/**
* @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");
require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
/**
* @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).
*
* This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
*/
function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
// 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 cannot use {Address-functionCall} here since this should return false
// and not revert is the subcall reverts.
(bool success, bytes memory returndata) = address(token).call(data);
return
success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @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
*
* Furthermore, `isContract` will also return true if the target contract within
* the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
* which only has an effect at the end of a transaction.
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 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://consensys.net/diligence/blog/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/v0.8.0/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");
(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 functionCallWithValue(target, data, 0, "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");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResultFromTarget(target, 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) {
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResultFromTarget(target, 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) {
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
* the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
*
* _Available since v4.8._
*/
function verifyCallResultFromTarget(
address target,
bool success,
bytes memory returndata,
string memory errorMessage
) internal view returns (bytes memory) {
if (success) {
if (returndata.length == 0) {
// only check isContract if the call was successful and the return data is empty
// otherwise we already know that it was a contract
require(isContract(target), "Address: call to non-contract");
}
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
/**
* @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason or using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
function _revert(bytes memory returndata, string memory errorMessage) private pure {
// 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
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IHasher {
function poseidon(bytes32[2] calldata inputs) external pure returns (bytes32);
function poseidon(bytes32[3] calldata inputs) external pure returns (bytes32);
function MiMCSponge(
uint256 in_xL,
uint256 in_xR
) external pure returns (uint256 xL, uint256 xR);
}
// https://tornado.cash
/*
* d888888P dP a88888b. dP
* 88 88 d8' `88 88
* 88 .d8888b. 88d888b. 88d888b. .d8888b. .d888b88 .d8888b. 88 .d8888b. .d8888b. 88d888b.
* 88 88' `88 88' `88 88' `88 88' `88 88' `88 88' `88 88 88' `88 Y8ooooo. 88' `88
* 88 88. .88 88 88 88 88. .88 88. .88 88. .88 dP Y8. .88 88. .88 88 88 88
* dP `88888P' dP dP dP `88888P8 `88888P8 `88888P' 88 Y88888P' `88888P8 `88888P' dP dP
* ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
*/
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./Tornado.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
contract ERC20Tornado is Tornado {
using SafeERC20 for IERC20;
IERC20 public token;
constructor(
IVerifier _verifier,
IHasher _hasher,
uint256 _denomination,
uint32 _merkleTreeHeight,
IERC20 _token
) Tornado(_verifier, _hasher, _denomination, _merkleTreeHeight) {
token = _token;
}
function _processDeposit() internal override {
require(
msg.value == 0,
"ETH value is supposed to be 0 for ERC20 instance"
);
token.safeTransferFrom(msg.sender, address(this), denomination);
}
function _processWithdraw(
address payable _recipient,
address payable _relayer,
uint256 _fee,
uint256 _refund
) internal override {
require(
msg.value == _refund,
"Incorrect refund amount received by the contract"
);
token.safeTransfer(_recipient, denomination - _fee);
if (_fee > 0) {
token.safeTransfer(_relayer, _fee);
}
if (_refund > 0) {
(bool success, ) = _recipient.call{value: _refund}("");
if (!success) {
// let's return _refund back to the relayer
_relayer.transfer(_refund);
}
}
}
}
// https://tornado.cash
/*
* d888888P dP a88888b. dP
* 88 88 d8' `88 88
* 88 .d8888b. 88d888b. 88d888b. .d8888b. .d888b88 .d8888b. 88 .d8888b. .d8888b. 88d888b.
* 88 88' `88 88' `88 88' `88 88' `88 88' `88 88' `88 88 88' `88 Y8ooooo. 88' `88
* 88 88. .88 88 88 88 88. .88 88. .88 88. .88 dP Y8. .88 88. .88 88 88 88
* dP `88888P' dP dP dP `88888P8 `88888P8 `88888P' 88 Y88888P' `88888P8 `88888P' dP dP
* ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
*/
import "../interfaces/IHasher.sol";
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract MerkleTreeWithHistory {
uint256 public constant FIELD_SIZE =
21888242871839275222246405745257275088548364400416034343698204186575808495617;
uint256 public constant ZERO_VALUE =
21663839004416932945382355908790599225266501822907911457504978515578255421292; // = keccak256("tornado") % FIELD_SIZE
IHasher public immutable hasher;
uint32 public levels;
// the following variables are made public for easier testing and debugging and
// are not supposed to be accessed in regular code
// filledSubtrees and roots could be bytes32[size], but using mappings makes it cheaper because
// it removes index range check on every interaction
mapping(uint256 => bytes32) public filledSubtrees;
mapping(uint256 => bytes32) public roots;
uint32 public constant ROOT_HISTORY_SIZE = 30;
uint32 public currentRootIndex = 0;
uint32 public nextIndex = 0;
constructor(uint32 _levels, IHasher _hasher) {
require(_levels > 0, "_levels should be greater than zero");
require(_levels < 32, "_levels should be less than 32");
levels = _levels;
hasher = _hasher;
for (uint32 i = 0; i < _levels; i++) {
filledSubtrees[i] = zeros(i);
}
roots[0] = zeros(_levels - 1);
}
/**
@dev Hash 2 tree leaves, returns MiMC(_left, _right)
*/
function hashLeftRight(
IHasher _hasher,
bytes32 _left,
bytes32 _right
) public pure returns (bytes32) {
require(
uint256(_left) < FIELD_SIZE,
"_left should be inside the field"
);
require(
uint256(_right) < FIELD_SIZE,
"_right should be inside the field"
);
uint256 R = uint256(_left);
uint256 C = 0;
(R, C) = _hasher.MiMCSponge(R, C);
R = addmod(R, uint256(_right), FIELD_SIZE);
(R, C) = _hasher.MiMCSponge(R, C);
return bytes32(R);
}
function _insert(bytes32 _leaf) internal returns (uint32 index) {
uint32 _nextIndex = nextIndex;
require(
_nextIndex != uint32(2) ** levels,
"Merkle tree is full. No more leaves can be added"
);
uint32 currentIndex = _nextIndex;
bytes32 currentLevelHash = _leaf;
bytes32 left;
bytes32 right;
for (uint32 i = 0; i < levels; i++) {
if (currentIndex % 2 == 0) {
left = currentLevelHash;
right = zeros(i);
filledSubtrees[i] = currentLevelHash;
} else {
left = filledSubtrees[i];
right = currentLevelHash;
}
currentLevelHash = hashLeftRight(hasher, left, right);
currentIndex /= 2;
}
uint32 newRootIndex = (currentRootIndex + 1) % ROOT_HISTORY_SIZE;
currentRootIndex = newRootIndex;
roots[newRootIndex] = currentLevelHash;
nextIndex = _nextIndex + 1;
return _nextIndex;
}
/**
@dev Whether the root is present in the root history
*/
function isKnownRoot(bytes32 _root) public view returns (bool) {
if (_root == 0) {
return false;
}
uint32 _currentRootIndex = currentRootIndex;
uint32 i = _currentRootIndex;
do {
if (_root == roots[i]) {
return true;
}
if (i == 0) {
i = ROOT_HISTORY_SIZE;
}
i--;
} while (i != _currentRootIndex);
return false;
}
/**
@dev Returns the last root
*/
function getLastRoot() public view returns (bytes32) {
return roots[currentRootIndex];
}
/// @dev provides Zero (Empty) elements for a MiMC MerkleTree. Up to 32 levels
function zeros(uint256 i) public pure returns (bytes32) {
if (i == 0)
return
bytes32(
0x2fe54c60d3acabf3343a35b6eba15db4821b340f76e741e2249685ed4899af6c
);
else if (i == 1)
return
bytes32(
0x256a6135777eee2fd26f54b8b7037a25439d5235caee224154186d2b8a52e31d
);
else if (i == 2)
return
bytes32(
0x1151949895e82ab19924de92c40a3d6f7bcb60d92b00504b8199613683f0c200
);
else if (i == 3)
return
bytes32(
0x20121ee811489ff8d61f09fb89e313f14959a0f28bb428a20dba6b0b068b3bdb
);
else if (i == 4)
return
bytes32(
0x0a89ca6ffa14cc462cfedb842c30ed221a50a3d6bf022a6a57dc82ab24c157c9
);
else if (i == 5)
return
bytes32(
0x24ca05c2b5cd42e890d6be94c68d0689f4f21c9cec9c0f13fe41d566dfb54959
);
else if (i == 6)
return
bytes32(
0x1ccb97c932565a92c60156bdba2d08f3bf1377464e025cee765679e604a7315c
);
else if (i == 7)
return
bytes32(
0x19156fbd7d1a8bf5cba8909367de1b624534ebab4f0f79e003bccdd1b182bdb4
);
else if (i == 8)
return
bytes32(
0x261af8c1f0912e465744641409f622d466c3920ac6e5ff37e36604cb11dfff80
);
else if (i == 9)
return
bytes32(
0x0058459724ff6ca5a1652fcbc3e82b93895cf08e975b19beab3f54c217d1c007
);
else if (i == 10)
return
bytes32(
0x1f04ef20dee48d39984d8eabe768a70eafa6310ad20849d4573c3c40c2ad1e30
);
else if (i == 11)
return
bytes32(
0x1bea3dec5dab51567ce7e200a30f7ba6d4276aeaa53e2686f962a46c66d511e5
);
else if (i == 12)
return
bytes32(
0x0ee0f941e2da4b9e31c3ca97a40d8fa9ce68d97c084177071b3cb46cd3372f0f
);
else if (i == 13)
return
bytes32(
0x1ca9503e8935884501bbaf20be14eb4c46b89772c97b96e3b2ebf3a36a948bbd
);
else if (i == 14)
return
bytes32(
0x133a80e30697cd55d8f7d4b0965b7be24057ba5dc3da898ee2187232446cb108
);
else if (i == 15)
return
bytes32(
0x13e6d8fc88839ed76e182c2a779af5b2c0da9dd18c90427a644f7e148a6253b6
);
else if (i == 16)
return
bytes32(
0x1eb16b057a477f4bc8f572ea6bee39561098f78f15bfb3699dcbb7bd8db61854
);
else if (i == 17)
return
bytes32(
0x0da2cb16a1ceaabf1c16b838f7a9e3f2a3a3088d9e0a6debaa748114620696ea
);
else if (i == 18)
return
bytes32(
0x24a3b3d822420b14b5d8cb6c28a574f01e98ea9e940551d2ebd75cee12649f9d
);
else if (i == 19)
return
bytes32(
0x198622acbd783d1b0d9064105b1fc8e4d8889de95c4c519b3f635809fe6afc05
);
else if (i == 20)
return
bytes32(
0x29d7ed391256ccc3ea596c86e933b89ff339d25ea8ddced975ae2fe30b5296d4
);
else if (i == 21)
return
bytes32(
0x19be59f2f0413ce78c0c3703a3a5451b1d7f39629fa33abd11548a76065b2967
);
else if (i == 22)
return
bytes32(
0x1ff3f61797e538b70e619310d33f2a063e7eb59104e112e95738da1254dc3453
);
else if (i == 23)
return
bytes32(
0x10c16ae9959cf8358980d9dd9616e48228737310a10e2b6b731c1a548f036c48
);
else if (i == 24)
return
bytes32(
0x0ba433a63174a90ac20992e75e3095496812b652685b5e1a2eae0b1bf4e8fcd1
);
else if (i == 25)
return
bytes32(
0x019ddb9df2bc98d987d0dfeca9d2b643deafab8f7036562e627c3667266a044c
);
else if (i == 26)
return
bytes32(
0x2d3c88b23175c5a5565db928414c66d1912b11acf974b2e644caaac04739ce99
);
else if (i == 27)
return
bytes32(
0x2eab55f6ae4e66e32c5189eed5c470840863445760f5ed7e7b69b2a62600f354
);
else if (i == 28)
return
bytes32(
0x002df37a2642621802383cf952bf4dd1f32e05433beeb1fd41031fb7eace979d
);
else if (i == 29)
return
bytes32(
0x104aeb41435db66c3e62feccc1d6f5d98d0a0ed75d1374db457cf462e3a1f427
);
else if (i == 30)
return
bytes32(
0x1f3c6fd858e9a7d4b0d1f38e256a09d81d5a5e3c963987e2d4b814cfab7c6ebb
);
else if (i == 31)
return
bytes32(
0x2c7a07d20dff79d01fecedc1134284a8d08436606c93693b67e333f671bf69cc
);
else revert("Index out of bounds");
}
}
// https://tornado.cash
/*
* d888888P dP a88888b. dP
* 88 88 d8' `88 88
* 88 .d8888b. 88d888b. 88d888b. .d8888b. .d888b88 .d8888b. 88 .d8888b. .d8888b. 88d888b.
* 88 88' `88 88' `88 88' `88 88' `88 88' `88 88' `88 88 88' `88 Y8ooooo. 88' `88
* 88 88. .88 88 88 88 88. .88 88. .88 88. .88 dP Y8. .88 88. .88 88 88 88
* dP `88888P' dP dP dP `88888P8 `88888P8 `88888P' 88 Y88888P' `88888P8 `88888P' dP dP
* ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
*/
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./MerkleTreeWithHistory.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
interface IVerifier {
function verifyProof(
bytes memory _proof,
uint256[6] memory _input
) external returns (bool);
}
abstract contract Tornado is MerkleTreeWithHistory, ReentrancyGuard {
IVerifier public immutable verifier;
uint256 public denomination;
mapping(bytes32 => bool) public nullifierHashes;
// we store all commitments just to prevent accidental deposits with the same commitment
mapping(bytes32 => bool) public commitments;
event Deposit(
bytes32 indexed commitment,
uint32 leafIndex,
uint256 timestamp
);
event Withdrawal(
address to,
bytes32 nullifierHash,
address indexed relayer,
uint256 fee
);
/**
@dev The constructor
@param _verifier the address of SNARK verifier for this contract
@param _hasher the address of MiMC hash contract
@param _denomination transfer amount for each deposit
@param _merkleTreeHeight the height of deposits' Merkle Tree
*/
constructor(
IVerifier _verifier,
IHasher _hasher,
uint256 _denomination,
uint32 _merkleTreeHeight
) MerkleTreeWithHistory(_merkleTreeHeight, _hasher) {
require(_denomination > 0, "denomination should be greater than 0");
verifier = _verifier;
denomination = _denomination;
}
/**
@dev Deposit funds into the contract. The caller must send (for ETH) or approve (for ERC20) value equal to or `denomination` of this instance.
@param _commitment the note commitment, which is PedersenHash(nullifier + secret)
*/
function deposit(bytes32 _commitment) external payable nonReentrant {
require(!commitments[_commitment], "The commitment has been submitted");
uint32 insertedIndex = _insert(_commitment);
commitments[_commitment] = true;
_processDeposit();
emit Deposit(_commitment, insertedIndex, block.timestamp);
}
/** @dev this function is defined in a child contract */
function _processDeposit() internal virtual;
/**
@dev Withdraw a deposit from the contract. `proof` is a zkSNARK proof data, and input is an array of circuit public inputs
`input` array consists of:
- merkle root of all deposits in the contract
- hash of unique deposit nullifier to prevent double spends
- the recipient of funds
- optional fee that goes to the transaction sender (usually a relay)
*/
function withdraw(
bytes calldata _proof,
bytes32 _root,
bytes32 _nullifierHash,
address payable _recipient,
address payable _relayer,
uint256 _fee,
uint256 _refund
) external payable nonReentrant {
require(_fee <= denomination, "Fee exceeds transfer value");
require(
!nullifierHashes[_nullifierHash],
"The note has been already spent"
);
require(isKnownRoot(_root), "Cannot find your merkle root"); // Make sure to use a recent one
require(verifier.verifyProof(_proof, [uint256(_root), uint256(_nullifierHash), uint256(uint160(address(_recipient))), uint256(uint160(address(_relayer))), _fee, _refund]), "Invalid withdraw proof");
nullifierHashes[_nullifierHash] = true;
_processWithdraw(_recipient, _relayer, _fee, _refund);
emit Withdrawal(_recipient, _nullifierHash, _relayer, _fee);
}
/** @dev this function is defined in a child contract */
function _processWithdraw(
address payable _recipient,
address payable _relayer,
uint256 _fee,
uint256 _refund
) internal virtual;
/** @dev whether a note is already spent */
function isSpent(bytes32 _nullifierHash) public view returns (bool) {
return nullifierHashes[_nullifierHash];
}
/** @dev whether an array of notes is already spent */
function isSpentArray(
bytes32[] calldata _nullifierHashes
) external view returns (bool[] memory spent) {
spent = new bool[](_nullifierHashes.length);
for (uint256 i = 0; i < _nullifierHashes.length; i++) {
if (isSpent(_nullifierHashes[i])) {
spent[i] = true;
}
}
}
}