{"ERC20Interface.sol":{"content":"// SPDX-License-Identifier: UNLICENSED\npragma solidity 0.7.5;\n\n/**\n * Contract that exposes the needed erc20 token functions\n */\n\nabstract contract ERC20Interface {\n  // Send _value amount of tokens to address _to\n  function transfer(address _to, uint256 _value)\n    public\n    virtual\n    returns (bool success);\n\n  // Get the account balance of another account with address _owner\n  function balanceOf(address _owner)\n    public\n    virtual\n    view\n    returns (uint256 balance);\n}\n"},"Forwarder.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\npragma solidity 0.7.5;\nimport \u0027./TransferHelper.sol\u0027;\nimport \u0027./ERC20Interface.sol\u0027;\n\n/**\n * Contract that will forward any incoming Ether to the creator of the contract\n *\n */\ncontract Forwarder {\n  // Address to which any funds sent to this contract will be forwarded\n  address public parentAddress;\n  event ForwarderDeposited(address from, uint256 value, bytes data);\n\n  /**\n   * Initialize the contract, and sets the destination address to that of the creator\n   */\n  function init(address _parentAddress) external onlyUninitialized {\n    parentAddress = _parentAddress;\n    uint256 value = address(this).balance;\n\n    if (value == 0) {\n      return;\n    }\n\n    (bool success, ) = parentAddress.call{ value: value }(\u0027\u0027);\n    require(success, \u0027Flush failed\u0027);\n    // NOTE: since we are forwarding on initialization,\n    // we don\u0027t have the context of the original sender.\n    // We still emit an event about the forwarding but set\n    // the sender to the forwarder itself\n    emit ForwarderDeposited(address(this), value, msg.data);\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the sender is the parent address\n   */\n  modifier onlyParent {\n    require(msg.sender == parentAddress, \u0027Only Parent\u0027);\n    _;\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the contract has not been initialized yet\n   */\n  modifier onlyUninitialized {\n    require(parentAddress == address(0x0), \u0027Already initialized\u0027);\n    _;\n  }\n\n  /**\n   * Default function; Gets called when data is sent but does not match any other function\n   */\n  fallback() external payable {\n    flush();\n  }\n\n  /**\n   * Default function; Gets called when Ether is deposited with no data, and forwards it to the parent address\n   */\n  receive() external payable {\n    flush();\n  }\n\n  /**\n   * Execute a token transfer of the full balance from the forwarder token to the parent address\n   * @param tokenContractAddress the address of the erc20 token contract\n   */\n  function flushTokens(address tokenContractAddress) external onlyParent {\n    ERC20Interface instance = ERC20Interface(tokenContractAddress);\n    address forwarderAddress = address(this);\n    uint256 forwarderBalance = instance.balanceOf(forwarderAddress);\n    if (forwarderBalance == 0) {\n      return;\n    }\n\n    TransferHelper.safeTransfer(\n      tokenContractAddress,\n      parentAddress,\n      forwarderBalance\n    );\n  }\n\n  /**\n   * Flush the entire balance of the contract to the parent address.\n   */\n  function flush() public {\n    uint256 value = address(this).balance;\n\n    if (value == 0) {\n      return;\n    }\n\n    (bool success, ) = parentAddress.call{ value: value }(\u0027\u0027);\n    require(success, \u0027Flush failed\u0027);\n    emit ForwarderDeposited(msg.sender, value, msg.data);\n  }\n}\n"},"TransferHelper.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\n\npragma solidity \u003e=0.7.5;\n\n// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false\nlibrary TransferHelper {\n    function safeApprove(\n        address token,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027approve(address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::safeApprove: approve failed\u0027\n        );\n    }\n\n    function safeTransfer(\n        address token,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027transfer(address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::safeTransfer: transfer failed\u0027\n        );\n    }\n\n    function safeTransferFrom(\n        address token,\n        address from,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027transferFrom(address,address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::transferFrom: transferFrom failed\u0027\n        );\n    }\n\n    function safeTransferETH(address to, uint256 value) internal {\n        (bool success, ) = to.call{value: value}(new bytes(0));\n        require(success, \u0027TransferHelper::safeTransferETH: ETH transfer failed\u0027);\n    }\n}\n"},"WalletSimple.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\npragma solidity 0.7.5;\nimport \u0027./TransferHelper.sol\u0027;\nimport \u0027./Forwarder.sol\u0027;\nimport \u0027./ERC20Interface.sol\u0027;\n\n/**\n *\n * WalletSimple\n * ============\n *\n * Basic multi-signer wallet designed for use in a co-signing environment where 2 signatures are required to move funds.\n * Typically used in a 2-of-3 signing configuration. Uses ecrecover to allow for 2 signatures in a single transaction.\n *\n * The first signature is created on the operation hash (see Data Formats) and passed to sendMultiSig/sendMultiSigToken\n * The signer is determined by verifyMultiSig().\n *\n * The second signature is created by the submitter of the transaction and determined by msg.signer.\n *\n * Data Formats\n * ============\n *\n * The signature is created with ethereumjs-util.ecsign(operationHash).\n * Like the eth_sign RPC call, it packs the values as a 65-byte array of [r, s, v].\n * Unlike eth_sign, the message is not prefixed.\n *\n * The operationHash the result of keccak256(prefix, toAddress, value, data, expireTime).\n * For ether transactions, `prefix` is \"ETHER\".\n * For token transaction, `prefix` is \"ERC20\" and `data` is the tokenContractAddress.\n *\n *\n */\ncontract WalletSimple {\n  // Events\n  event Deposited(address from, uint256 value, bytes data);\n  event SafeModeActivated(address msgSender);\n  event Transacted(\n    address msgSender, // Address of the sender of the message initiating the transaction\n    address otherSigner, // Address of the signer (second signature) used to initiate the transaction\n    bytes32 operation, // Operation hash (see Data Formats)\n    address toAddress, // The address the transaction was sent to\n    uint256 value, // Amount of Wei sent to the address\n    bytes data // Data sent when invoking the transaction\n  );\n\n  event BatchTransfer(address sender, address recipient, uint256 value);\n  // this event shows the other signer and the operation hash that they signed\n  // specific batch transfer events are emitted in Batcher\n  event BatchTransacted(\n    address msgSender, // Address of the sender of the message initiating the transaction\n    address otherSigner, // Address of the signer (second signature) used to initiate the transaction\n    bytes32 operation // Operation hash (see Data Formats)\n  );\n\n  // Public fields\n  mapping(address =\u003e bool) public signers; // The addresses that can co-sign transactions on the wallet\n  bool public safeMode = false; // When active, wallet may only send to signer addresses\n  bool public initialized = false; // True if the contract has been initialized\n\n  // Internal fields\n  uint256 private constant MAX_SEQUENCE_ID_INCREASE = 10000;\n  uint256 constant SEQUENCE_ID_WINDOW_SIZE = 10;\n  uint256[SEQUENCE_ID_WINDOW_SIZE] recentSequenceIds;\n\n  /**\n   * Set up a simple multi-sig wallet by specifying the signers allowed to be used on this wallet.\n   * 2 signers will be required to send a transaction from this wallet.\n   * Note: The sender is NOT automatically added to the list of signers.\n   * Signers CANNOT be changed once they are set\n   *\n   * @param allowedSigners An array of signers on the wallet\n   */\n  function init(address[] calldata allowedSigners) external onlyUninitialized {\n    require(allowedSigners.length == 3, \u0027Invalid number of signers\u0027);\n\n    for (uint8 i = 0; i \u003c allowedSigners.length; i++) {\n      require(allowedSigners[i] != address(0), \u0027Invalid signer\u0027);\n      signers[allowedSigners[i]] = true;\n    }\n    initialized = true;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ETHER\u0027;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over for token transfers\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getTokenNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ERC20\u0027;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over for batch transfers\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getBatchNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ETHER-Batch\u0027;\n  }\n\n  /**\n   * Determine if an address is a signer on this wallet\n   * @param signer address to check\n   * returns boolean indicating whether address is signer or not\n   */\n  function isSigner(address signer) public view returns (bool) {\n    return signers[signer];\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the sender is an authorized signer on this wallet\n   */\n  modifier onlySigner {\n    require(isSigner(msg.sender), \u0027Non-signer in onlySigner method\u0027);\n    _;\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the contract has not been initialized yet\n   */\n  modifier onlyUninitialized {\n    require(!initialized, \u0027Contract already initialized\u0027);\n    _;\n  }\n\n  /**\n   * Gets called when a transaction is received with data that does not match any other method\n   */\n  fallback() external payable {\n    if (msg.value \u003e 0) {\n      // Fire deposited event if we are receiving funds\n      Deposited(msg.sender, msg.value, msg.data);\n    }\n  }\n\n  /**\n   * Gets called when a transaction is received with ether and no data\n   */\n  receive() external payable {\n    if (msg.value \u003e 0) {\n      // Fire deposited event if we are receiving funds\n      Deposited(msg.sender, msg.value, msg.data);\n    }\n  }\n\n  /**\n   * Execute a multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param value the amount in Wei to be sent\n   * @param data the data to send to the toAddress when invoking the transaction\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSig(\n    address toAddress,\n    uint256 value,\n    bytes calldata data,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getNetworkId(),\n        toAddress,\n        value,\n        data,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    address otherSigner = verifyMultiSig(\n      toAddress,\n      operationHash,\n      signature,\n      expireTime,\n      sequenceId\n    );\n\n    // Success, send the transaction\n    (bool success, ) = toAddress.call{ value: value }(data);\n    require(success, \u0027Call execution failed\u0027);\n\n    emit Transacted(\n      msg.sender,\n      otherSigner,\n      operationHash,\n      toAddress,\n      value,\n      data\n    );\n  }\n\n  /**\n   * Execute a batched multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   * The recipients and values to send are encoded in two arrays, where for index i, recipients[i] will be sent values[i].\n   *\n   * @param recipients The list of recipients to send to\n   * @param values The list of values to send to\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSigBatch(\n    address[] calldata recipients,\n    uint256[] calldata values,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    require(recipients.length != 0, \u0027Not enough recipients\u0027);\n    require(\n      recipients.length == values.length,\n      \u0027Unequal recipients and values\u0027\n    );\n    require(recipients.length \u003c 256, \u0027Too many recipients, max 255\u0027);\n\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getBatchNetworkId(),\n        recipients,\n        values,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    // the first parameter (toAddress) is used to ensure transactions in safe mode only go to a signer\n    // if in safe mode, we should use normal sendMultiSig to recover, so this check will always fail if in safe mode\n    require(!safeMode, \u0027Batch in safe mode\u0027);\n    address otherSigner = verifyMultiSig(\n      address(0x0),\n      operationHash,\n      signature,\n      expireTime,\n      sequenceId\n    );\n\n    batchTransfer(recipients, values);\n    emit BatchTransacted(msg.sender, otherSigner, operationHash);\n  }\n\n  /**\n   * Transfer funds in a batch to each of recipients\n   * @param recipients The list of recipients to send to\n   * @param values The list of values to send to recipients.\n   *  The recipient with index i in recipients array will be sent values[i].\n   *  Thus, recipients and values must be the same length\n   */\n  function batchTransfer(\n    address[] calldata recipients,\n    uint256[] calldata values\n  ) internal {\n    for (uint256 i = 0; i \u003c recipients.length; i++) {\n      require(address(this).balance \u003e= values[i], \u0027Insufficient funds\u0027);\n\n      (bool success, ) = recipients[i].call{ value: values[i] }(\u0027\u0027);\n      require(success, \u0027Call failed\u0027);\n\n      emit BatchTransfer(msg.sender, recipients[i], values[i]);\n    }\n  }\n\n  /**\n   * Execute a multi-signature token transfer from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param value the amount in tokens to be sent\n   * @param tokenContractAddress the address of the erc20 token contract\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSigToken(\n    address toAddress,\n    uint256 value,\n    address tokenContractAddress,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getTokenNetworkId(),\n        toAddress,\n        value,\n        tokenContractAddress,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);\n\n    TransferHelper.safeTransfer(tokenContractAddress, toAddress, value);\n  }\n\n  /**\n   * Execute a token flush from one of the forwarder addresses. This transfer needs only a single signature and can be done by any signer\n   *\n   * @param forwarderAddress the address of the forwarder address to flush the tokens from\n   * @param tokenContractAddress the address of the erc20 token contract\n   */\n  function flushForwarderTokens(\n    address payable forwarderAddress,\n    address tokenContractAddress\n  ) external onlySigner {\n    Forwarder forwarder = Forwarder(forwarderAddress);\n    forwarder.flushTokens(tokenContractAddress);\n  }\n\n  /**\n   * Do common multisig verification for both eth sends and erc20token transfers\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param operationHash see Data Formats\n   * @param signature see Data Formats\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * returns address that has created the signature\n   */\n  function verifyMultiSig(\n    address toAddress,\n    bytes32 operationHash,\n    bytes calldata signature,\n    uint256 expireTime,\n    uint256 sequenceId\n  ) private returns (address) {\n    address otherSigner = recoverAddressFromSignature(operationHash, signature);\n\n    // Verify if we are in safe mode. In safe mode, the wallet can only send to signers\n    require(!safeMode || isSigner(toAddress), \u0027External transfer in safe mode\u0027);\n\n    // Verify that the transaction has not expired\n    require(expireTime \u003e= block.timestamp, \u0027Transaction expired\u0027);\n\n    // Try to insert the sequence ID. Will revert if the sequence id was invalid\n    tryInsertSequenceId(sequenceId);\n\n    require(isSigner(otherSigner), \u0027Invalid signer\u0027);\n\n    require(otherSigner != msg.sender, \u0027Signers cannot be equal\u0027);\n\n    return otherSigner;\n  }\n\n  /**\n   * Irrevocably puts contract into safe mode. When in this mode, transactions may only be sent to signing addresses.\n   */\n  function activateSafeMode() external onlySigner {\n    safeMode = true;\n    SafeModeActivated(msg.sender);\n  }\n\n  /**\n   * Gets signer\u0027s address using ecrecover\n   * @param operationHash see Data Formats\n   * @param signature see Data Formats\n   * returns address recovered from the signature\n   */\n  function recoverAddressFromSignature(\n    bytes32 operationHash,\n    bytes memory signature\n  ) private pure returns (address) {\n    require(signature.length == 65, \u0027Invalid signature - wrong length\u0027);\n\n    // We need to unpack the signature, which is given as an array of 65 bytes (like eth.sign)\n    bytes32 r;\n    bytes32 s;\n    uint8 v;\n\n    // solhint-disable-next-line\n    assembly {\n      r := mload(add(signature, 32))\n      s := mload(add(signature, 64))\n      v := and(mload(add(signature, 65)), 255)\n    }\n    if (v \u003c 27) {\n      v += 27; // Ethereum versions are 27 or 28 as opposed to 0 or 1 which is submitted by some signing libs\n    }\n\n    // protect against signature malleability\n    // S value must be in the lower half orader\n    // reference: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/051d340171a93a3d401aaaea46b4b62fa81e5d7c/contracts/cryptography/ECDSA.sol#L53\n    require(\n      uint256(s) \u003c=\n        0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,\n      \"ECDSA: invalid signature \u0027s\u0027 value\"\n    );\n\n    // note that this returns 0 if the signature is invalid\n    // Since 0x0 can never be a signer, when the recovered signer address\n    // is checked against our signer list, that 0x0 will cause an invalid signer failure\n    return ecrecover(operationHash, v, r, s);\n  }\n\n  /**\n   * Verify that the sequence id has not been used before and inserts it. Throws if the sequence ID was not accepted.\n   * We collect a window of up to 10 recent sequence ids, and allow any sequence id that is not in the window and\n   * greater than the minimum element in the window.\n   * @param sequenceId to insert into array of stored ids\n   */\n  function tryInsertSequenceId(uint256 sequenceId) private onlySigner {\n    // Keep a pointer to the lowest value element in the window\n    uint256 lowestValueIndex = 0;\n    // fetch recentSequenceIds into memory for function context to avoid unnecessary sloads\n    uint256[SEQUENCE_ID_WINDOW_SIZE] memory _recentSequenceIds = recentSequenceIds;\n    for (uint256 i = 0; i \u003c SEQUENCE_ID_WINDOW_SIZE; i++) {\n      require(_recentSequenceIds[i] != sequenceId, \u0027Sequence ID already used\u0027);\n\n      if (_recentSequenceIds[i] \u003c _recentSequenceIds[lowestValueIndex]) {\n        lowestValueIndex = i;\n      }\n    }\n\n    // The sequence ID being used is lower than the lowest value in the window\n    // so we cannot accept it as it may have been used before\n    require(\n      sequenceId \u003e _recentSequenceIds[lowestValueIndex],\n      \u0027Sequence ID below window\u0027\n    );\n\n    // Block sequence IDs which are much higher than the lowest value\n    // This prevents people blocking the contract by using very large sequence IDs quickly\n    require(\n      sequenceId \u003c=\n        (_recentSequenceIds[lowestValueIndex] + MAX_SEQUENCE_ID_INCREASE),\n      \u0027Sequence ID above maximum\u0027\n    );\n\n    recentSequenceIds[lowestValueIndex] = sequenceId;\n  }\n\n  /**\n   * Gets the next available sequence ID for signing when using executeAndConfirm\n   * returns the sequenceId one higher than the highest currently stored\n   */\n  function getNextSequenceId() public view returns (uint256) {\n    uint256 highestSequenceId = 0;\n    for (uint256 i = 0; i \u003c SEQUENCE_ID_WINDOW_SIZE; i++) {\n      if (recentSequenceIds[i] \u003e highestSequenceId) {\n        highestSequenceId = recentSequenceIds[i];\n      }\n    }\n    return highestSequenceId + 1;\n  }\n}\n"}}

pragma solidity ^0.4.17;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        assert(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address public owner;

    /**
      * @dev The Ownable constructor sets the original `owner` of the contract to the sender
      * account.
      */
    function Ownable() public {
        owner = msg.sender;
    }

    /**
      * @dev Throws if called by any account other than the owner.
      */
    modifier onlyOwner() {
        require(msg.sender == 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) public onlyOwner {
        if (newOwner != address(0)) {
            owner = newOwner;
        }
    }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20Basic {
    uint public _totalSupply;
    function totalSupply() public constant returns (uint);
    function balanceOf(address who) public constant returns (uint);
    function transfer(address to, uint value) public;
    event Transfer(address indexed from, address indexed to, uint value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public constant returns (uint);
    function transferFrom(address from, address to, uint value) public;
    function approve(address spender, uint value) public;
    event Approval(address indexed owner, address indexed spender, uint value);
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is Ownable, ERC20Basic {
    using SafeMath for uint;

    mapping(address => uint) public balances;

    // additional variables for use if transaction fees ever became necessary
    uint public basisPointsRate = 0;
    uint public maximumFee = 0;

    /**
    * @dev Fix for the ERC20 short address attack.
    */
    modifier onlyPayloadSize(uint size) {
        require(!(msg.data.length < size + 4));
        _;
    }

    /**
    * @dev transfer token for a specified address
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint _value) public onlyPayloadSize(2 * 32) {
        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        uint sendAmount = _value.sub(fee);
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(msg.sender, owner, fee);
        }
        Transfer(msg.sender, _to, sendAmount);
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public constant returns (uint balance) {
        return balances[_owner];
    }

}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based oncode by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is BasicToken, ERC20 {

    mapping (address => mapping (address => uint)) public allowed;

    uint public constant MAX_UINT = 2**256 - 1;

    /**
    * @dev Transfer tokens from one address to another
    * @param _from address The address which you want to send tokens from
    * @param _to address The address which you want to transfer to
    * @param _value uint the amount of tokens to be transferred
    */
    function transferFrom(address _from, address _to, uint _value) public onlyPayloadSize(3 * 32) {
        var _allowance = allowed[_from][msg.sender];

        // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
        // if (_value > _allowance) throw;

        uint fee = (_value.mul(basisPointsRate)).div(10000);
        if (fee > maximumFee) {
            fee = maximumFee;
        }
        if (_allowance < MAX_UINT) {
            allowed[_from][msg.sender] = _allowance.sub(_value);
        }
        uint sendAmount = _value.sub(fee);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(sendAmount);
        if (fee > 0) {
            balances[owner] = balances[owner].add(fee);
            Transfer(_from, owner, fee);
        }
        Transfer(_from, _to, sendAmount);
    }

    /**
    * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
    * @param _spender The address which will spend the funds.
    * @param _value The amount of tokens to be spent.
    */
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {

        // To change the approve amount you first have to reduce the addresses`
        //  allowance to zero by calling `approve(_spender, 0)` if it is not
        //  already 0 to mitigate the race condition described here:
        //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
        require(!((_value != 0) && (allowed[msg.sender][_spender] != 0)));

        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
    }

    /**
    * @dev Function to check the amount of tokens than an owner allowed to a spender.
    * @param _owner address The address which owns the funds.
    * @param _spender address The address which will spend the funds.
    * @return A uint specifying the amount of tokens still available for the spender.
    */
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        return allowed[_owner][_spender];
    }

}


/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    Unpause();
  }
}

contract BlackList is Ownable, BasicToken {

    /////// Getters to allow the same blacklist to be used also by other contracts (including upgraded Tether) ///////
    function getBlackListStatus(address _maker) external constant returns (bool) {
        return isBlackListed[_maker];
    }

    function getOwner() external constant returns (address) {
        return owner;
    }

    mapping (address => bool) public isBlackListed;
    
    function addBlackList (address _evilUser) public onlyOwner {
        isBlackListed[_evilUser] = true;
        AddedBlackList(_evilUser);
    }

    function removeBlackList (address _clearedUser) public onlyOwner {
        isBlackListed[_clearedUser] = false;
        RemovedBlackList(_clearedUser);
    }

    function destroyBlackFunds (address _blackListedUser) public onlyOwner {
        require(isBlackListed[_blackListedUser]);
        uint dirtyFunds = balanceOf(_blackListedUser);
        balances[_blackListedUser] = 0;
        _totalSupply -= dirtyFunds;
        DestroyedBlackFunds(_blackListedUser, dirtyFunds);
    }

    event DestroyedBlackFunds(address _blackListedUser, uint _balance);

    event AddedBlackList(address _user);

    event RemovedBlackList(address _user);

}

contract UpgradedStandardToken is StandardToken{
    // those methods are called by the legacy contract
    // and they must ensure msg.sender to be the contract address
    function transferByLegacy(address from, address to, uint value) public;
    function transferFromByLegacy(address sender, address from, address spender, uint value) public;
    function approveByLegacy(address from, address spender, uint value) public;
}

contract TetherToken is Pausable, StandardToken, BlackList {

    string public name;
    string public symbol;
    uint public decimals;
    address public upgradedAddress;
    bool public deprecated;

    //  The contract can be initialized with a number of tokens
    //  All the tokens are deposited to the owner address
    //
    // @param _balance Initial supply of the contract
    // @param _name Token Name
    // @param _symbol Token symbol
    // @param _decimals Token decimals
    function TetherToken(uint _initialSupply, string _name, string _symbol, uint _decimals) public {
        _totalSupply = _initialSupply;
        name = _name;
        symbol = _symbol;
        decimals = _decimals;
        balances[owner] = _initialSupply;
        deprecated = false;
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transfer(address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[msg.sender]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferByLegacy(msg.sender, _to, _value);
        } else {
            return super.transfer(_to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function transferFrom(address _from, address _to, uint _value) public whenNotPaused {
        require(!isBlackListed[_from]);
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).transferFromByLegacy(msg.sender, _from, _to, _value);
        } else {
            return super.transferFrom(_from, _to, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function balanceOf(address who) public constant returns (uint) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).balanceOf(who);
        } else {
            return super.balanceOf(who);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function approve(address _spender, uint _value) public onlyPayloadSize(2 * 32) {
        if (deprecated) {
            return UpgradedStandardToken(upgradedAddress).approveByLegacy(msg.sender, _spender, _value);
        } else {
            return super.approve(_spender, _value);
        }
    }

    // Forward ERC20 methods to upgraded contract if this one is deprecated
    function allowance(address _owner, address _spender) public constant returns (uint remaining) {
        if (deprecated) {
            return StandardToken(upgradedAddress).allowance(_owner, _spender);
        } else {
            return super.allowance(_owner, _spender);
        }
    }

    // deprecate current contract in favour of a new one
    function deprecate(address _upgradedAddress) public onlyOwner {
        deprecated = true;
        upgradedAddress = _upgradedAddress;
        Deprecate(_upgradedAddress);
    }

    // deprecate current contract if favour of a new one
    function totalSupply() public constant returns (uint) {
        if (deprecated) {
            return StandardToken(upgradedAddress).totalSupply();
        } else {
            return _totalSupply;
        }
    }

    // Issue a new amount of tokens
    // these tokens are deposited into the owner address
    //
    // @param _amount Number of tokens to be issued
    function issue(uint amount) public onlyOwner {
        require(_totalSupply + amount > _totalSupply);
        require(balances[owner] + amount > balances[owner]);

        balances[owner] += amount;
        _totalSupply += amount;
        Issue(amount);
    }

    // Redeem tokens.
    // These tokens are withdrawn from the owner address
    // if the balance must be enough to cover the redeem
    // or the call will fail.
    // @param _amount Number of tokens to be issued
    function redeem(uint amount) public onlyOwner {
        require(_totalSupply >= amount);
        require(balances[owner] >= amount);

        _totalSupply -= amount;
        balances[owner] -= amount;
        Redeem(amount);
    }

    function setParams(uint newBasisPoints, uint newMaxFee) public onlyOwner {
        // Ensure transparency by hardcoding limit beyond which fees can never be added
        require(newBasisPoints < 20);
        require(newMaxFee < 50);

        basisPointsRate = newBasisPoints;
        maximumFee = newMaxFee.mul(10**decimals);

        Params(basisPointsRate, maximumFee);
    }

    // Called when new token are issued
    event Issue(uint amount);

    // Called when tokens are redeemed
    event Redeem(uint amount);

    // Called when contract is deprecated
    event Deprecate(address newAddress);

    // Called if contract ever adds fees
    event Params(uint feeBasisPoints, uint maxFee);
}

{"ERC20Interface.sol":{"content":"// SPDX-License-Identifier: UNLICENSED\npragma solidity 0.7.5;\n\n/**\n * Contract that exposes the needed erc20 token functions\n */\n\nabstract contract ERC20Interface {\n  // Send _value amount of tokens to address _to\n  function transfer(address _to, uint256 _value)\n    public\n    virtual\n    returns (bool success);\n\n  // Get the account balance of another account with address _owner\n  function balanceOf(address _owner)\n    public\n    virtual\n    view\n    returns (uint256 balance);\n}\n"},"Forwarder.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\npragma solidity 0.7.5;\nimport \u0027./TransferHelper.sol\u0027;\nimport \u0027./ERC20Interface.sol\u0027;\n\n/**\n * Contract that will forward any incoming Ether to the creator of the contract\n *\n */\ncontract Forwarder {\n  // Address to which any funds sent to this contract will be forwarded\n  address public parentAddress;\n  event ForwarderDeposited(address from, uint256 value, bytes data);\n\n  /**\n   * Initialize the contract, and sets the destination address to that of the creator\n   */\n  function init(address _parentAddress) external onlyUninitialized {\n    parentAddress = _parentAddress;\n    uint256 value = address(this).balance;\n\n    if (value == 0) {\n      return;\n    }\n\n    (bool success, ) = parentAddress.call{ value: value }(\u0027\u0027);\n    require(success, \u0027Flush failed\u0027);\n    // NOTE: since we are forwarding on initialization,\n    // we don\u0027t have the context of the original sender.\n    // We still emit an event about the forwarding but set\n    // the sender to the forwarder itself\n    emit ForwarderDeposited(address(this), value, msg.data);\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the sender is the parent address\n   */\n  modifier onlyParent {\n    require(msg.sender == parentAddress, \u0027Only Parent\u0027);\n    _;\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the contract has not been initialized yet\n   */\n  modifier onlyUninitialized {\n    require(parentAddress == address(0x0), \u0027Already initialized\u0027);\n    _;\n  }\n\n  /**\n   * Default function; Gets called when data is sent but does not match any other function\n   */\n  fallback() external payable {\n    flush();\n  }\n\n  /**\n   * Default function; Gets called when Ether is deposited with no data, and forwards it to the parent address\n   */\n  receive() external payable {\n    flush();\n  }\n\n  /**\n   * Execute a token transfer of the full balance from the forwarder token to the parent address\n   * @param tokenContractAddress the address of the erc20 token contract\n   */\n  function flushTokens(address tokenContractAddress) external onlyParent {\n    ERC20Interface instance = ERC20Interface(tokenContractAddress);\n    address forwarderAddress = address(this);\n    uint256 forwarderBalance = instance.balanceOf(forwarderAddress);\n    if (forwarderBalance == 0) {\n      return;\n    }\n\n    TransferHelper.safeTransfer(\n      tokenContractAddress,\n      parentAddress,\n      forwarderBalance\n    );\n  }\n\n  /**\n   * Flush the entire balance of the contract to the parent address.\n   */\n  function flush() public {\n    uint256 value = address(this).balance;\n\n    if (value == 0) {\n      return;\n    }\n\n    (bool success, ) = parentAddress.call{ value: value }(\u0027\u0027);\n    require(success, \u0027Flush failed\u0027);\n    emit ForwarderDeposited(msg.sender, value, msg.data);\n  }\n}\n"},"TransferHelper.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\n\npragma solidity \u003e=0.7.5;\n\n// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false\nlibrary TransferHelper {\n    function safeApprove(\n        address token,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027approve(address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::safeApprove: approve failed\u0027\n        );\n    }\n\n    function safeTransfer(\n        address token,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027transfer(address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::safeTransfer: transfer failed\u0027\n        );\n    }\n\n    function safeTransferFrom(\n        address token,\n        address from,\n        address to,\n        uint256 value\n    ) internal {\n        // bytes4(keccak256(bytes(\u0027transferFrom(address,address,uint256)\u0027)));\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));\n        require(\n            success \u0026\u0026 (data.length == 0 || abi.decode(data, (bool))),\n            \u0027TransferHelper::transferFrom: transferFrom failed\u0027\n        );\n    }\n\n    function safeTransferETH(address to, uint256 value) internal {\n        (bool success, ) = to.call{value: value}(new bytes(0));\n        require(success, \u0027TransferHelper::safeTransferETH: ETH transfer failed\u0027);\n    }\n}\n"},"WalletSimple.sol":{"content":"// SPDX-License-Identifier: Apache-2.0\npragma solidity 0.7.5;\nimport \u0027./TransferHelper.sol\u0027;\nimport \u0027./Forwarder.sol\u0027;\nimport \u0027./ERC20Interface.sol\u0027;\n\n/**\n *\n * WalletSimple\n * ============\n *\n * Basic multi-signer wallet designed for use in a co-signing environment where 2 signatures are required to move funds.\n * Typically used in a 2-of-3 signing configuration. Uses ecrecover to allow for 2 signatures in a single transaction.\n *\n * The first signature is created on the operation hash (see Data Formats) and passed to sendMultiSig/sendMultiSigToken\n * The signer is determined by verifyMultiSig().\n *\n * The second signature is created by the submitter of the transaction and determined by msg.signer.\n *\n * Data Formats\n * ============\n *\n * The signature is created with ethereumjs-util.ecsign(operationHash).\n * Like the eth_sign RPC call, it packs the values as a 65-byte array of [r, s, v].\n * Unlike eth_sign, the message is not prefixed.\n *\n * The operationHash the result of keccak256(prefix, toAddress, value, data, expireTime).\n * For ether transactions, `prefix` is \"ETHER\".\n * For token transaction, `prefix` is \"ERC20\" and `data` is the tokenContractAddress.\n *\n *\n */\ncontract WalletSimple {\n  // Events\n  event Deposited(address from, uint256 value, bytes data);\n  event SafeModeActivated(address msgSender);\n  event Transacted(\n    address msgSender, // Address of the sender of the message initiating the transaction\n    address otherSigner, // Address of the signer (second signature) used to initiate the transaction\n    bytes32 operation, // Operation hash (see Data Formats)\n    address toAddress, // The address the transaction was sent to\n    uint256 value, // Amount of Wei sent to the address\n    bytes data // Data sent when invoking the transaction\n  );\n\n  event BatchTransfer(address sender, address recipient, uint256 value);\n  // this event shows the other signer and the operation hash that they signed\n  // specific batch transfer events are emitted in Batcher\n  event BatchTransacted(\n    address msgSender, // Address of the sender of the message initiating the transaction\n    address otherSigner, // Address of the signer (second signature) used to initiate the transaction\n    bytes32 operation // Operation hash (see Data Formats)\n  );\n\n  // Public fields\n  mapping(address =\u003e bool) public signers; // The addresses that can co-sign transactions on the wallet\n  bool public safeMode = false; // When active, wallet may only send to signer addresses\n  bool public initialized = false; // True if the contract has been initialized\n\n  // Internal fields\n  uint256 private constant MAX_SEQUENCE_ID_INCREASE = 10000;\n  uint256 constant SEQUENCE_ID_WINDOW_SIZE = 10;\n  uint256[SEQUENCE_ID_WINDOW_SIZE] recentSequenceIds;\n\n  /**\n   * Set up a simple multi-sig wallet by specifying the signers allowed to be used on this wallet.\n   * 2 signers will be required to send a transaction from this wallet.\n   * Note: The sender is NOT automatically added to the list of signers.\n   * Signers CANNOT be changed once they are set\n   *\n   * @param allowedSigners An array of signers on the wallet\n   */\n  function init(address[] calldata allowedSigners) external onlyUninitialized {\n    require(allowedSigners.length == 3, \u0027Invalid number of signers\u0027);\n\n    for (uint8 i = 0; i \u003c allowedSigners.length; i++) {\n      require(allowedSigners[i] != address(0), \u0027Invalid signer\u0027);\n      signers[allowedSigners[i]] = true;\n    }\n    initialized = true;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ETHER\u0027;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over for token transfers\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getTokenNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ERC20\u0027;\n  }\n\n  /**\n   * Get the network identifier that signers must sign over for batch transfers\n   * This provides protection signatures being replayed on other chains\n   * This must be a virtual function because chain-specific contracts will need\n   *    to override with their own network ids. It also can\u0027t be a field\n   *    to allow this contract to be used by proxy with delegatecall, which will\n   *    not pick up on state variables\n   */\n  function getBatchNetworkId() internal virtual pure returns (string memory) {\n    return \u0027ETHER-Batch\u0027;\n  }\n\n  /**\n   * Determine if an address is a signer on this wallet\n   * @param signer address to check\n   * returns boolean indicating whether address is signer or not\n   */\n  function isSigner(address signer) public view returns (bool) {\n    return signers[signer];\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the sender is an authorized signer on this wallet\n   */\n  modifier onlySigner {\n    require(isSigner(msg.sender), \u0027Non-signer in onlySigner method\u0027);\n    _;\n  }\n\n  /**\n   * Modifier that will execute internal code block only if the contract has not been initialized yet\n   */\n  modifier onlyUninitialized {\n    require(!initialized, \u0027Contract already initialized\u0027);\n    _;\n  }\n\n  /**\n   * Gets called when a transaction is received with data that does not match any other method\n   */\n  fallback() external payable {\n    if (msg.value \u003e 0) {\n      // Fire deposited event if we are receiving funds\n      Deposited(msg.sender, msg.value, msg.data);\n    }\n  }\n\n  /**\n   * Gets called when a transaction is received with ether and no data\n   */\n  receive() external payable {\n    if (msg.value \u003e 0) {\n      // Fire deposited event if we are receiving funds\n      Deposited(msg.sender, msg.value, msg.data);\n    }\n  }\n\n  /**\n   * Execute a multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param value the amount in Wei to be sent\n   * @param data the data to send to the toAddress when invoking the transaction\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSig(\n    address toAddress,\n    uint256 value,\n    bytes calldata data,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getNetworkId(),\n        toAddress,\n        value,\n        data,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    address otherSigner = verifyMultiSig(\n      toAddress,\n      operationHash,\n      signature,\n      expireTime,\n      sequenceId\n    );\n\n    // Success, send the transaction\n    (bool success, ) = toAddress.call{ value: value }(data);\n    require(success, \u0027Call execution failed\u0027);\n\n    emit Transacted(\n      msg.sender,\n      otherSigner,\n      operationHash,\n      toAddress,\n      value,\n      data\n    );\n  }\n\n  /**\n   * Execute a batched multi-signature transaction from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   * The recipients and values to send are encoded in two arrays, where for index i, recipients[i] will be sent values[i].\n   *\n   * @param recipients The list of recipients to send to\n   * @param values The list of values to send to\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSigBatch(\n    address[] calldata recipients,\n    uint256[] calldata values,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    require(recipients.length != 0, \u0027Not enough recipients\u0027);\n    require(\n      recipients.length == values.length,\n      \u0027Unequal recipients and values\u0027\n    );\n    require(recipients.length \u003c 256, \u0027Too many recipients, max 255\u0027);\n\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getBatchNetworkId(),\n        recipients,\n        values,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    // the first parameter (toAddress) is used to ensure transactions in safe mode only go to a signer\n    // if in safe mode, we should use normal sendMultiSig to recover, so this check will always fail if in safe mode\n    require(!safeMode, \u0027Batch in safe mode\u0027);\n    address otherSigner = verifyMultiSig(\n      address(0x0),\n      operationHash,\n      signature,\n      expireTime,\n      sequenceId\n    );\n\n    batchTransfer(recipients, values);\n    emit BatchTransacted(msg.sender, otherSigner, operationHash);\n  }\n\n  /**\n   * Transfer funds in a batch to each of recipients\n   * @param recipients The list of recipients to send to\n   * @param values The list of values to send to recipients.\n   *  The recipient with index i in recipients array will be sent values[i].\n   *  Thus, recipients and values must be the same length\n   */\n  function batchTransfer(\n    address[] calldata recipients,\n    uint256[] calldata values\n  ) internal {\n    for (uint256 i = 0; i \u003c recipients.length; i++) {\n      require(address(this).balance \u003e= values[i], \u0027Insufficient funds\u0027);\n\n      (bool success, ) = recipients[i].call{ value: values[i] }(\u0027\u0027);\n      require(success, \u0027Call failed\u0027);\n\n      emit BatchTransfer(msg.sender, recipients[i], values[i]);\n    }\n  }\n\n  /**\n   * Execute a multi-signature token transfer from this wallet using 2 signers: one from msg.sender and the other from ecrecover.\n   * Sequence IDs are numbers starting from 1. They are used to prevent replay attacks and may not be repeated.\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param value the amount in tokens to be sent\n   * @param tokenContractAddress the address of the erc20 token contract\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * @param signature see Data Formats\n   */\n  function sendMultiSigToken(\n    address toAddress,\n    uint256 value,\n    address tokenContractAddress,\n    uint256 expireTime,\n    uint256 sequenceId,\n    bytes calldata signature\n  ) external onlySigner {\n    // Verify the other signer\n    bytes32 operationHash = keccak256(\n      abi.encodePacked(\n        getTokenNetworkId(),\n        toAddress,\n        value,\n        tokenContractAddress,\n        expireTime,\n        sequenceId\n      )\n    );\n\n    verifyMultiSig(toAddress, operationHash, signature, expireTime, sequenceId);\n\n    TransferHelper.safeTransfer(tokenContractAddress, toAddress, value);\n  }\n\n  /**\n   * Execute a token flush from one of the forwarder addresses. This transfer needs only a single signature and can be done by any signer\n   *\n   * @param forwarderAddress the address of the forwarder address to flush the tokens from\n   * @param tokenContractAddress the address of the erc20 token contract\n   */\n  function flushForwarderTokens(\n    address payable forwarderAddress,\n    address tokenContractAddress\n  ) external onlySigner {\n    Forwarder forwarder = Forwarder(forwarderAddress);\n    forwarder.flushTokens(tokenContractAddress);\n  }\n\n  /**\n   * Do common multisig verification for both eth sends and erc20token transfers\n   *\n   * @param toAddress the destination address to send an outgoing transaction\n   * @param operationHash see Data Formats\n   * @param signature see Data Formats\n   * @param expireTime the number of seconds since 1970 for which this transaction is valid\n   * @param sequenceId the unique sequence id obtainable from getNextSequenceId\n   * returns address that has created the signature\n   */\n  function verifyMultiSig(\n    address toAddress,\n    bytes32 operationHash,\n    bytes calldata signature,\n    uint256 expireTime,\n    uint256 sequenceId\n  ) private returns (address) {\n    address otherSigner = recoverAddressFromSignature(operationHash, signature);\n\n    // Verify if we are in safe mode. In safe mode, the wallet can only send to signers\n    require(!safeMode || isSigner(toAddress), \u0027External transfer in safe mode\u0027);\n\n    // Verify that the transaction has not expired\n    require(expireTime \u003e= block.timestamp, \u0027Transaction expired\u0027);\n\n    // Try to insert the sequence ID. Will revert if the sequence id was invalid\n    tryInsertSequenceId(sequenceId);\n\n    require(isSigner(otherSigner), \u0027Invalid signer\u0027);\n\n    require(otherSigner != msg.sender, \u0027Signers cannot be equal\u0027);\n\n    return otherSigner;\n  }\n\n  /**\n   * Irrevocably puts contract into safe mode. When in this mode, transactions may only be sent to signing addresses.\n   */\n  function activateSafeMode() external onlySigner {\n    safeMode = true;\n    SafeModeActivated(msg.sender);\n  }\n\n  /**\n   * Gets signer\u0027s address using ecrecover\n   * @param operationHash see Data Formats\n   * @param signature see Data Formats\n   * returns address recovered from the signature\n   */\n  function recoverAddressFromSignature(\n    bytes32 operationHash,\n    bytes memory signature\n  ) private pure returns (address) {\n    require(signature.length == 65, \u0027Invalid signature - wrong length\u0027);\n\n    // We need to unpack the signature, which is given as an array of 65 bytes (like eth.sign)\n    bytes32 r;\n    bytes32 s;\n    uint8 v;\n\n    // solhint-disable-next-line\n    assembly {\n      r := mload(add(signature, 32))\n      s := mload(add(signature, 64))\n      v := and(mload(add(signature, 65)), 255)\n    }\n    if (v \u003c 27) {\n      v += 27; // Ethereum versions are 27 or 28 as opposed to 0 or 1 which is submitted by some signing libs\n    }\n\n    // protect against signature malleability\n    // S value must be in the lower half orader\n    // reference: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/051d340171a93a3d401aaaea46b4b62fa81e5d7c/contracts/cryptography/ECDSA.sol#L53\n    require(\n      uint256(s) \u003c=\n        0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,\n      \"ECDSA: invalid signature \u0027s\u0027 value\"\n    );\n\n    // note that this returns 0 if the signature is invalid\n    // Since 0x0 can never be a signer, when the recovered signer address\n    // is checked against our signer list, that 0x0 will cause an invalid signer failure\n    return ecrecover(operationHash, v, r, s);\n  }\n\n  /**\n   * Verify that the sequence id has not been used before and inserts it. Throws if the sequence ID was not accepted.\n   * We collect a window of up to 10 recent sequence ids, and allow any sequence id that is not in the window and\n   * greater than the minimum element in the window.\n   * @param sequenceId to insert into array of stored ids\n   */\n  function tryInsertSequenceId(uint256 sequenceId) private onlySigner {\n    // Keep a pointer to the lowest value element in the window\n    uint256 lowestValueIndex = 0;\n    // fetch recentSequenceIds into memory for function context to avoid unnecessary sloads\n    uint256[SEQUENCE_ID_WINDOW_SIZE] memory _recentSequenceIds = recentSequenceIds;\n    for (uint256 i = 0; i \u003c SEQUENCE_ID_WINDOW_SIZE; i++) {\n      require(_recentSequenceIds[i] != sequenceId, \u0027Sequence ID already used\u0027);\n\n      if (_recentSequenceIds[i] \u003c _recentSequenceIds[lowestValueIndex]) {\n        lowestValueIndex = i;\n      }\n    }\n\n    // The sequence ID being used is lower than the lowest value in the window\n    // so we cannot accept it as it may have been used before\n    require(\n      sequenceId \u003e _recentSequenceIds[lowestValueIndex],\n      \u0027Sequence ID below window\u0027\n    );\n\n    // Block sequence IDs which are much higher than the lowest value\n    // This prevents people blocking the contract by using very large sequence IDs quickly\n    require(\n      sequenceId \u003c=\n        (_recentSequenceIds[lowestValueIndex] + MAX_SEQUENCE_ID_INCREASE),\n      \u0027Sequence ID above maximum\u0027\n    );\n\n    recentSequenceIds[lowestValueIndex] = sequenceId;\n  }\n\n  /**\n   * Gets the next available sequence ID for signing when using executeAndConfirm\n   * returns the sequenceId one higher than the highest currently stored\n   */\n  function getNextSequenceId() public view returns (uint256) {\n    uint256 highestSequenceId = 0;\n    for (uint256 i = 0; i \u003c SEQUENCE_ID_WINDOW_SIZE; i++) {\n      if (recentSequenceIds[i] \u003e highestSequenceId) {\n        highestSequenceId = recentSequenceIds[i];\n      }\n    }\n    return highestSequenceId + 1;\n  }\n}\n"}}