307 lines
11 KiB
Solidity
307 lines
11 KiB
Solidity
// SPDX-License-Identifier: MIT
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// https://tornado.cash
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/*
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* d888888P dP a88888b. dP
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* 88 88 d8' `88 88
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* 88 .d8888b. 88d888b. 88d888b. .d8888b. .d888b88 .d8888b. 88 .d8888b. .d8888b. 88d888b.
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* 88 88' `88 88' `88 88' `88 88' `88 88' `88 88' `88 88 88' `88 Y8ooooo. 88' `88
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* 88 88. .88 88 88 88 88. .88 88. .88 88. .88 dP Y8. .88 88. .88 88 88 88
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* dP `88888P' dP dP dP `88888P8 `88888P8 `88888P' 88 Y88888P' `88888P8 `88888P' dP dP
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* ooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
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*/
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pragma solidity ^0.7.0;
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pragma experimental ABIEncoderV2;
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import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
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import { IERC20Receiver, IERC6777, IOmniBridge } from "./interfaces/IBridge.sol";
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import { CrossChainGuard } from "./bridge/CrossChainGuard.sol";
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import { IVerifier } from "./interfaces/IVerifier.sol";
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import "./MerkleTreeWithHistory.sol";
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/** @dev This contract(pool) allows deposit of an arbitrary amount to it, shielded transfer to another registered user inside the pool
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* and withdrawal from the pool. Project utilizes UTXO model to handle users' funds.
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*/
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contract TornadoPool is MerkleTreeWithHistory, IERC20Receiver, ReentrancyGuard, CrossChainGuard {
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int256 public constant MAX_EXT_AMOUNT = 2**248;
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uint256 public constant MAX_FEE = 2**248;
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IVerifier public immutable verifier2;
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IVerifier public immutable verifier16;
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IERC6777 public immutable token;
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address public immutable omniBridge;
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address public immutable l1Unwrapper;
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address public immutable multisig;
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uint256 public lastBalance;
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uint256 public minimalWithdrawalAmount;
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uint256 public maximumDepositAmount;
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mapping(bytes32 => bool) public nullifierHashes;
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struct ExtData {
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address recipient;
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int256 extAmount;
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address relayer;
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uint256 fee;
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bytes encryptedOutput1;
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bytes encryptedOutput2;
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bool isL1Withdrawal;
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uint256 l1Fee;
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}
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struct Proof {
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bytes proof;
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bytes32 root;
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bytes32[] inputNullifiers;
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bytes32[2] outputCommitments;
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uint256 publicAmount;
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bytes32 extDataHash;
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}
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struct Account {
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address owner;
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bytes publicKey;
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}
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event NewCommitment(bytes32 commitment, uint256 index, bytes encryptedOutput);
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event NewNullifier(bytes32 nullifier);
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event PublicKey(address indexed owner, bytes key);
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modifier onlyGovernance() {
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require(isCalledByOwner(), "only governance");
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_;
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}
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modifier onlyMultisig() {
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require(msg.sender == multisig, "only governance");
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_;
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}
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/**
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@dev The constructor
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@param _verifier2 the address of SNARK verifier for 2 inputs
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@param _verifier16 the address of SNARK verifier for 16 inputs
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@param _levels hight of the commitments merkle tree
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@param _hasher hasher address for the merkle tree
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@param _token token address for the pool
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@param _omniBridge omniBridge address for specified token
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@param _l1Unwrapper address of the L1Helper
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@param _governance owner address
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@param _l1ChainId chain id of L1
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@param _multisig multisig on L2
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*/
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constructor(
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IVerifier _verifier2,
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IVerifier _verifier16,
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uint32 _levels,
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address _hasher,
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IERC6777 _token,
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address _omniBridge,
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address _l1Unwrapper,
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address _governance,
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uint256 _l1ChainId,
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address _multisig
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)
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MerkleTreeWithHistory(_levels, _hasher)
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CrossChainGuard(address(IOmniBridge(_omniBridge).bridgeContract()), _l1ChainId, _governance)
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{
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verifier2 = _verifier2;
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verifier16 = _verifier16;
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token = _token;
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omniBridge = _omniBridge;
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l1Unwrapper = _l1Unwrapper;
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multisig = _multisig;
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}
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function initialize(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) external initializer {
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_configureLimits(_minimalWithdrawalAmount, _maximumDepositAmount);
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super._initialize();
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}
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/** @dev Main function that allows deposits, transfers and withdrawal.
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*/
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function transact(Proof memory _args, ExtData memory _extData) public {
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if (_extData.extAmount > 0) {
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// for deposits from L2
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token.transferFrom(msg.sender, address(this), uint256(_extData.extAmount));
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require(uint256(_extData.extAmount) <= maximumDepositAmount, "amount is larger than maximumDepositAmount");
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}
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_transact(_args, _extData);
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}
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function register(Account memory _account) public {
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require(_account.owner == msg.sender, "only owner can be registered");
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_register(_account);
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}
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function registerAndTransact(
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Account memory _account,
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Proof memory _proofArgs,
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ExtData memory _extData
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) public {
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register(_account);
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transact(_proofArgs, _extData);
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}
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function onTokenBridged(
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IERC6777 _token,
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uint256 _amount,
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bytes calldata _data
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) external override {
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(Proof memory _args, ExtData memory _extData) = abi.decode(_data, (Proof, ExtData));
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require(_token == token, "provided token is not supported");
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require(msg.sender == omniBridge, "only omni bridge");
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require(_amount >= uint256(_extData.extAmount), "amount from bridge is incorrect");
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require(token.balanceOf(address(this)) >= uint256(_extData.extAmount) + lastBalance, "bridge did not send enough tokens");
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require(uint256(_extData.extAmount) <= maximumDepositAmount, "amount is larger than maximumDepositAmount");
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uint256 sentAmount = token.balanceOf(address(this)) - lastBalance;
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try TornadoPool(address(this)).onTransact(_args, _extData) {} catch (bytes memory) {
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token.transfer(multisig, sentAmount);
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}
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}
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/**
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* @dev Wrapper for the internal func _transact to call it using try-catch from onTokenBridged
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*/
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function onTransact(Proof memory _args, ExtData memory _extData) external {
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require(msg.sender == address(this), "can be called only from onTokenBridged");
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_transact(_args, _extData);
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}
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/// @dev Method to claim junk and accidentally sent tokens
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function rescueTokens(
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IERC6777 _token,
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address payable _to,
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uint256 _balance
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) external onlyMultisig {
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require(_to != address(0), "TORN: can not send to zero address");
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require(_token != token, "can not rescue pool asset");
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if (_token == IERC6777(0)) {
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// for Ether
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uint256 totalBalance = address(this).balance;
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uint256 balance = _balance == 0 ? totalBalance : _balance;
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_to.transfer(balance);
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} else {
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// any other erc20
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uint256 totalBalance = _token.balanceOf(address(this));
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uint256 balance = _balance == 0 ? totalBalance : _balance;
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require(balance > 0, "TORN: trying to send 0 balance");
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_token.transfer(_to, balance);
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}
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}
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function configureLimits(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) public onlyGovernance {
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_configureLimits(_minimalWithdrawalAmount, _maximumDepositAmount);
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}
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function calculatePublicAmount(int256 _extAmount, uint256 _fee) public pure returns (uint256) {
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require(_fee < MAX_FEE, "Invalid fee");
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require(_extAmount > -MAX_EXT_AMOUNT && _extAmount < MAX_EXT_AMOUNT, "Invalid ext amount");
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int256 publicAmount = _extAmount - int256(_fee);
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return (publicAmount >= 0) ? uint256(publicAmount) : FIELD_SIZE - uint256(-publicAmount);
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}
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/** @dev whether a note is already spent */
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function isSpent(bytes32 _nullifierHash) public view returns (bool) {
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return nullifierHashes[_nullifierHash];
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}
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function verifyProof(Proof memory _args) public view returns (bool) {
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if (_args.inputNullifiers.length == 2) {
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return
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verifier2.verifyProof(
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_args.proof,
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[
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uint256(_args.root),
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_args.publicAmount,
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uint256(_args.extDataHash),
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uint256(_args.inputNullifiers[0]),
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uint256(_args.inputNullifiers[1]),
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uint256(_args.outputCommitments[0]),
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uint256(_args.outputCommitments[1])
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]
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);
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} else if (_args.inputNullifiers.length == 16) {
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return
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verifier16.verifyProof(
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_args.proof,
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[
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uint256(_args.root),
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_args.publicAmount,
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uint256(_args.extDataHash),
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uint256(_args.inputNullifiers[0]),
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uint256(_args.inputNullifiers[1]),
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uint256(_args.inputNullifiers[2]),
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uint256(_args.inputNullifiers[3]),
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uint256(_args.inputNullifiers[4]),
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uint256(_args.inputNullifiers[5]),
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uint256(_args.inputNullifiers[6]),
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uint256(_args.inputNullifiers[7]),
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uint256(_args.inputNullifiers[8]),
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uint256(_args.inputNullifiers[9]),
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uint256(_args.inputNullifiers[10]),
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uint256(_args.inputNullifiers[11]),
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uint256(_args.inputNullifiers[12]),
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uint256(_args.inputNullifiers[13]),
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uint256(_args.inputNullifiers[14]),
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uint256(_args.inputNullifiers[15]),
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uint256(_args.outputCommitments[0]),
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uint256(_args.outputCommitments[1])
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]
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);
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} else {
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revert("unsupported input count");
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}
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}
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function _register(Account memory _account) internal {
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emit PublicKey(_account.owner, _account.publicKey);
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}
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function _transact(Proof memory _args, ExtData memory _extData) internal nonReentrant {
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require(isKnownRoot(_args.root), "Invalid merkle root");
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for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
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require(!isSpent(_args.inputNullifiers[i]), "Input is already spent");
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}
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require(uint256(_args.extDataHash) == uint256(keccak256(abi.encode(_extData))) % FIELD_SIZE, "Incorrect external data hash");
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require(_args.publicAmount == calculatePublicAmount(_extData.extAmount, _extData.fee), "Invalid public amount");
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require(verifyProof(_args), "Invalid transaction proof");
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for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
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nullifierHashes[_args.inputNullifiers[i]] = true;
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}
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if (_extData.extAmount < 0) {
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require(_extData.recipient != address(0), "Can't withdraw to zero address");
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if (_extData.isL1Withdrawal) {
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token.transferAndCall(
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omniBridge,
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uint256(-_extData.extAmount),
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abi.encodePacked(l1Unwrapper, _extData.recipient, _extData.l1Fee)
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);
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} else {
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token.transfer(_extData.recipient, uint256(-_extData.extAmount));
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}
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require(uint256(-_extData.extAmount) >= minimalWithdrawalAmount, "amount is less than minimalWithdrawalAmount"); // prevents ddos attack to Bridge
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}
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if (_extData.fee > 0) {
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token.transfer(_extData.relayer, _extData.fee);
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}
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lastBalance = token.balanceOf(address(this));
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_insert(_args.outputCommitments[0], _args.outputCommitments[1]);
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emit NewCommitment(_args.outputCommitments[0], nextIndex - 2, _extData.encryptedOutput1);
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emit NewCommitment(_args.outputCommitments[1], nextIndex - 1, _extData.encryptedOutput2);
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for (uint256 i = 0; i < _args.inputNullifiers.length; i++) {
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emit NewNullifier(_args.inputNullifiers[i]);
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}
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}
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function _configureLimits(uint256 _minimalWithdrawalAmount, uint256 _maximumDepositAmount) internal {
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minimalWithdrawalAmount = _minimalWithdrawalAmount;
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maximumDepositAmount = _maximumDepositAmount;
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}
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}
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