ETH Price: $1,965.81 (-2.26%)

Transaction Decoder

Block:
23823156 at Nov-18-2025 02:52:35 AM +UTC
Transaction Fee:
0.000061490864232501 ETH $0.12
Gas Used:
137,049 Gas / 0.448677949 Gwei

Emitted Events:

1131 FiatTokenProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x0000000000000000000000005ae13baaef0620fdae1d355495dc51a17adb4082, 0x000000000000000000000000fbd4cdb413e45a52e2c8312f670e9ce67e794c37, 00000000000000000000000000000000000000000000000000000000f0781f37 )
1132 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000fbd4cdb413e45a52e2c8312f670e9ce67e794c37, 0x0000000000000000000000005ae13baaef0620fdae1d355495dc51a17adb4082, 0000000000000000000000000000000000000000000000000df9728e87e25609 )
1133 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000fbd4cdb413e45a52e2c8312f670e9ce67e794c37, 0x00000000000000000000000038699d04656ff537ef8671b6b595402ebdbdf6f4, 0000000000000000000000000000000000000000000000000000000000000000 )
1134 0x5ae13baaef0620fdae1d355495dc51a17adb4082.0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67( 0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67, 0x000000000000000000000000fbd4cdb413e45a52e2c8312f670e9ce67e794c37, 0x000000000000000000000000fbd4cdb413e45a52e2c8312f670e9ce67e794c37, 0000000000000000000000000000000000000000000000000df9728e87e25609, ffffffffffffffffffffffffffffffffffffffffffffffffffffffff0f87e0c9, 000000000000000000000000000000000000000000042632d9b1f3ce161834ff, 0000000000000000000000000000000000000000000000002062caa1c2bacd6d, fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffd0cb1 )

Account State Difference:

  Address   Before After State Difference Code
0x22B0351D...2DCB17e96
6.367375938728938822 Eth
Nonce: 96976
6.367314447840883165 Eth
Nonce: 96977
0.000061490888055657
0x45804880...E6EcbAf78
0x5aE13BAA...17adb4082
(Uniswap V3: PAXG-USDC)
0xA0b86991...E3606eB48
(BuilderNet)
184.097028856757616914 Eth184.097028967392477899 Eth0.000000110634860985
0xfBd4cdB4...67E794C37
(MEV Bot: 0xfBd...C37)
16.507647569963082348 Eth16.507647569986905504 Eth0.000000000023823156

Execution Trace

ETH 0.000000000023823156 MEV Bot: 0xfBd...C37.a0000000( )
  • Uniswap V3: PAXG-USDC.128acb08( )
    • FiatTokenProxy.a9059cbb( )
      • FiatTokenV2_2.transfer( to=0xfBd4cdB413E45a52E2C8312f670e9cE67E794C37, value=4034404151 ) => ( True )
      • AdminUpgradeabilityProxy.70a08231( )
        • PAXGImplementation.balanceOf( _addr=0x5aE13BAAEF0620FdaE1D355495Dc51a17adb4082 ) => ( 1496533638676063916330 )
        • MEV Bot: 0xfBd...C37.fa461e33( )
          • AdminUpgradeabilityProxy.a9059cbb( )
            • PAXGImplementation.transfer( _to=0x5aE13BAAEF0620FdaE1D355495Dc51a17adb4082, _value=1006961948184696329 ) => ( True )
            • AdminUpgradeabilityProxy.70a08231( )
              • PAXGImplementation.balanceOf( _addr=0x5aE13BAAEF0620FdaE1D355495Dc51a17adb4082 ) => ( 1497540600624248612659 )
                File 1 of 4: FiatTokenProxy
                pragma solidity ^0.4.24;
                
                // File: zos-lib/contracts/upgradeability/Proxy.sol
                
                /**
                 * @title Proxy
                 * @dev Implements delegation of calls to other contracts, with proper
                 * forwarding of return values and bubbling of failures.
                 * It defines a fallback function that delegates all calls to the address
                 * returned by the abstract _implementation() internal function.
                 */
                contract Proxy {
                  /**
                   * @dev Fallback function.
                   * Implemented entirely in `_fallback`.
                   */
                  function () payable external {
                    _fallback();
                  }
                
                  /**
                   * @return The Address of the implementation.
                   */
                  function _implementation() internal view returns (address);
                
                  /**
                   * @dev Delegates execution to an implementation contract.
                   * This is a low level function that doesn't return to its internal call site.
                   * It will return to the external caller whatever the implementation returns.
                   * @param implementation Address to delegate.
                   */
                  function _delegate(address implementation) internal {
                    assembly {
                      // Copy msg.data. We take full control of memory in this inline assembly
                      // block because it will not return to Solidity code. We overwrite the
                      // Solidity scratch pad at memory position 0.
                      calldatacopy(0, 0, calldatasize)
                
                      // Call the implementation.
                      // out and outsize are 0 because we don't know the size yet.
                      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                
                      // Copy the returned data.
                      returndatacopy(0, 0, returndatasize)
                
                      switch result
                      // delegatecall returns 0 on error.
                      case 0 { revert(0, returndatasize) }
                      default { return(0, returndatasize) }
                    }
                  }
                
                  /**
                   * @dev Function that is run as the first thing in the fallback function.
                   * Can be redefined in derived contracts to add functionality.
                   * Redefinitions must call super._willFallback().
                   */
                  function _willFallback() internal {
                  }
                
                  /**
                   * @dev fallback implementation.
                   * Extracted to enable manual triggering.
                   */
                  function _fallback() internal {
                    _willFallback();
                    _delegate(_implementation());
                  }
                }
                
                // File: openzeppelin-solidity/contracts/AddressUtils.sol
                
                /**
                 * Utility library of inline functions on addresses
                 */
                library AddressUtils {
                
                  /**
                   * Returns whether the target address is a contract
                   * @dev This function will return false if invoked during the constructor of a contract,
                   * as the code is not actually created until after the constructor finishes.
                   * @param addr address to check
                   * @return whether the target address is a contract
                   */
                  function isContract(address addr) internal view returns (bool) {
                    uint256 size;
                    // XXX Currently there is no better way to check if there is a contract in an address
                    // than to check the size of the code at that address.
                    // See https://ethereum.stackexchange.com/a/14016/36603
                    // for more details about how this works.
                    // TODO Check this again before the Serenity release, because all addresses will be
                    // contracts then.
                    // solium-disable-next-line security/no-inline-assembly
                    assembly { size := extcodesize(addr) }
                    return size > 0;
                  }
                
                }
                
                // File: zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol
                
                /**
                 * @title UpgradeabilityProxy
                 * @dev This contract implements a proxy that allows to change the
                 * implementation address to which it will delegate.
                 * Such a change is called an implementation upgrade.
                 */
                contract UpgradeabilityProxy is Proxy {
                  /**
                   * @dev Emitted when the implementation is upgraded.
                   * @param implementation Address of the new implementation.
                   */
                  event Upgraded(address implementation);
                
                  /**
                   * @dev Storage slot with the address of the current implementation.
                   * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                   * validated in the constructor.
                   */
                  bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                
                  /**
                   * @dev Contract constructor.
                   * @param _implementation Address of the initial implementation.
                   */
                  constructor(address _implementation) public {
                    assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                
                    _setImplementation(_implementation);
                  }
                
                  /**
                   * @dev Returns the current implementation.
                   * @return Address of the current implementation
                   */
                  function _implementation() internal view returns (address impl) {
                    bytes32 slot = IMPLEMENTATION_SLOT;
                    assembly {
                      impl := sload(slot)
                    }
                  }
                
                  /**
                   * @dev Upgrades the proxy to a new implementation.
                   * @param newImplementation Address of the new implementation.
                   */
                  function _upgradeTo(address newImplementation) internal {
                    _setImplementation(newImplementation);
                    emit Upgraded(newImplementation);
                  }
                
                  /**
                   * @dev Sets the implementation address of the proxy.
                   * @param newImplementation Address of the new implementation.
                   */
                  function _setImplementation(address newImplementation) private {
                    require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                
                    bytes32 slot = IMPLEMENTATION_SLOT;
                
                    assembly {
                      sstore(slot, newImplementation)
                    }
                  }
                }
                
                // File: zos-lib/contracts/upgradeability/AdminUpgradeabilityProxy.sol
                
                /**
                 * @title AdminUpgradeabilityProxy
                 * @dev This contract combines an upgradeability proxy with an authorization
                 * mechanism for administrative tasks.
                 * All external functions in this contract must be guarded by the
                 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                 * feature proposal that would enable this to be done automatically.
                 */
                contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                  /**
                   * @dev Emitted when the administration has been transferred.
                   * @param previousAdmin Address of the previous admin.
                   * @param newAdmin Address of the new admin.
                   */
                  event AdminChanged(address previousAdmin, address newAdmin);
                
                  /**
                   * @dev Storage slot with the admin of the contract.
                   * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                   * validated in the constructor.
                   */
                  bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                
                  /**
                   * @dev Modifier to check whether the `msg.sender` is the admin.
                   * If it is, it will run the function. Otherwise, it will delegate the call
                   * to the implementation.
                   */
                  modifier ifAdmin() {
                    if (msg.sender == _admin()) {
                      _;
                    } else {
                      _fallback();
                    }
                  }
                
                  /**
                   * Contract constructor.
                   * It sets the `msg.sender` as the proxy administrator.
                   * @param _implementation address of the initial implementation.
                   */
                  constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
                    assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                
                    _setAdmin(msg.sender);
                  }
                
                  /**
                   * @return The address of the proxy admin.
                   */
                  function admin() external view ifAdmin returns (address) {
                    return _admin();
                  }
                
                  /**
                   * @return The address of the implementation.
                   */
                  function implementation() external view ifAdmin returns (address) {
                    return _implementation();
                  }
                
                  /**
                   * @dev Changes the admin of the proxy.
                   * Only the current admin can call this function.
                   * @param newAdmin Address to transfer proxy administration to.
                   */
                  function changeAdmin(address newAdmin) external ifAdmin {
                    require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                    emit AdminChanged(_admin(), newAdmin);
                    _setAdmin(newAdmin);
                  }
                
                  /**
                   * @dev Upgrade the backing implementation of the proxy.
                   * Only the admin can call this function.
                   * @param newImplementation Address of the new implementation.
                   */
                  function upgradeTo(address newImplementation) external ifAdmin {
                    _upgradeTo(newImplementation);
                  }
                
                  /**
                   * @dev Upgrade the backing implementation of the proxy and call a function
                   * on the new implementation.
                   * This is useful to initialize the proxied contract.
                   * @param newImplementation Address of the new implementation.
                   * @param data Data to send as msg.data in the low level call.
                   * It should include the signature and the parameters of the function to be
                   * called, as described in
                   * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
                   */
                  function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                    _upgradeTo(newImplementation);
                    require(address(this).call.value(msg.value)(data));
                  }
                
                  /**
                   * @return The admin slot.
                   */
                  function _admin() internal view returns (address adm) {
                    bytes32 slot = ADMIN_SLOT;
                    assembly {
                      adm := sload(slot)
                    }
                  }
                
                  /**
                   * @dev Sets the address of the proxy admin.
                   * @param newAdmin Address of the new proxy admin.
                   */
                  function _setAdmin(address newAdmin) internal {
                    bytes32 slot = ADMIN_SLOT;
                
                    assembly {
                      sstore(slot, newAdmin)
                    }
                  }
                
                  /**
                   * @dev Only fall back when the sender is not the admin.
                   */
                  function _willFallback() internal {
                    require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                    super._willFallback();
                  }
                }
                
                // File: contracts/FiatTokenProxy.sol
                
                /**
                * Copyright CENTRE SECZ 2018
                *
                * Permission is hereby granted, free of charge, to any person obtaining a copy 
                * of this software and associated documentation files (the "Software"), to deal 
                * in the Software without restriction, including without limitation the rights 
                * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
                * copies of the Software, and to permit persons to whom the Software is furnished to 
                * do so, subject to the following conditions:
                *
                * The above copyright notice and this permission notice shall be included in all 
                * copies or substantial portions of the Software.
                *
                * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
                * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
                * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
                * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
                * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
                * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
                */
                
                pragma solidity ^0.4.24;
                
                
                /**
                 * @title FiatTokenProxy
                 * @dev This contract proxies FiatToken calls and enables FiatToken upgrades
                */ 
                contract FiatTokenProxy is AdminUpgradeabilityProxy {
                    constructor(address _implementation) public AdminUpgradeabilityProxy(_implementation) {
                    }
                }

                File 2 of 4: AdminUpgradeabilityProxy
                // File: contracts/zeppelin/Proxy.sol
                
                pragma solidity 0.4.24;
                
                /**
                 * @title Proxy
                 * @dev Implements delegation of calls to other contracts, with proper
                 * forwarding of return values and bubbling of failures.
                 * It defines a fallback function that delegates all calls to the address
                 * returned by the abstract _implementation() internal function.
                 */
                contract Proxy {
                    /**
                     * @dev Fallback function.
                     * Implemented entirely in `_fallback`.
                     */
                    function () payable external {
                        _fallback();
                    }
                
                    /**
                     * @return The Address of the implementation.
                     */
                    function _implementation() internal view returns (address);
                
                    /**
                     * @dev Delegates execution to an implementation contract.
                     * This is a low level function that doesn't return to its internal call site.
                     * It will return to the external caller whatever the implementation returns.
                     * @param implementation Address to delegate.
                     */
                    function _delegate(address implementation) internal {
                        assembly {
                        // Copy msg.data. We take full control of memory in this inline assembly
                        // block because it will not return to Solidity code. We overwrite the
                        // Solidity scratch pad at memory position 0.
                            calldatacopy(0, 0, calldatasize)
                
                        // Call the implementation.
                        // out and outsize are 0 because we don't know the size yet.
                            let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                
                        // Copy the returned data.
                            returndatacopy(0, 0, returndatasize)
                
                            switch result
                            // delegatecall returns 0 on error.
                            case 0 { revert(0, returndatasize) }
                            default { return(0, returndatasize) }
                        }
                    }
                
                    /**
                     * @dev Function that is run as the first thing in the fallback function.
                     * Can be redefined in derived contracts to add functionality.
                     * Redefinitions must call super._willFallback().
                     */
                    function _willFallback() internal {
                    }
                
                    /**
                     * @dev fallback implementation.
                     * Extracted to enable manual triggering.
                     */
                    function _fallback() internal {
                        _willFallback();
                        _delegate(_implementation());
                    }
                }
                
                // File: contracts/zeppelin/AddressUtils.sol
                
                pragma solidity 0.4.24;
                
                
                /**
                 * Utility library of inline functions on addresses
                 */
                library AddressUtils {
                
                    /**
                     * Returns whether the target address is a contract
                     * @dev This function will return false if invoked during the constructor of a contract,
                     * as the code is not actually created until after the constructor finishes.
                     * @param addr address to check
                     * @return whether the target address is a contract
                     */
                    function isContract(address addr) internal view returns (bool) {
                        uint256 size;
                        // XXX Currently there is no better way to check if there is a contract in an address
                        // than to check the size of the code at that address.
                        // See https://ethereum.stackexchange.com/a/14016/36603
                        // for more details about how this works.
                        // TODO Check this again before the Serenity release, because all addresses will be
                        // contracts then.
                        // solium-disable-next-line security/no-inline-assembly
                        assembly { size := extcodesize(addr) }
                        return size > 0;
                    }
                
                }
                
                // File: contracts/zeppelin/UpgradeabilityProxy.sol
                
                pragma solidity 0.4.24;
                
                
                
                /**
                 * @title UpgradeabilityProxy
                 * @dev This contract implements a proxy that allows to change the
                 * implementation address to which it will delegate.
                 * Such a change is called an implementation upgrade.
                 */
                contract UpgradeabilityProxy is Proxy {
                    /**
                     * @dev Emitted when the implementation is upgraded.
                     * @param implementation Address of the new implementation.
                     */
                    event Upgraded(address implementation);
                
                    /**
                     * @dev Storage slot with the address of the current implementation.
                     * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                     * validated in the constructor.
                     */
                    bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                
                    /**
                     * @dev Contract constructor.
                     * @param _implementation Address of the initial implementation.
                     */
                    constructor(address _implementation) public {
                        assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                
                        _setImplementation(_implementation);
                    }
                
                    /**
                     * @dev Returns the current implementation.
                     * @return Address of the current implementation
                     */
                    function _implementation() internal view returns (address impl) {
                        bytes32 slot = IMPLEMENTATION_SLOT;
                        assembly {
                            impl := sload(slot)
                        }
                    }
                
                    /**
                     * @dev Upgrades the proxy to a new implementation.
                     * @param newImplementation Address of the new implementation.
                     */
                    function _upgradeTo(address newImplementation) internal {
                        _setImplementation(newImplementation);
                        emit Upgraded(newImplementation);
                    }
                
                    /**
                     * @dev Sets the implementation address of the proxy.
                     * @param newImplementation Address of the new implementation.
                     */
                    function _setImplementation(address newImplementation) private {
                        require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                
                        bytes32 slot = IMPLEMENTATION_SLOT;
                
                        assembly {
                            sstore(slot, newImplementation)
                        }
                    }
                }
                
                // File: contracts/zeppelin/AdminUpgradeabilityProxy.sol
                
                pragma solidity 0.4.24;
                
                
                /**
                 * @title AdminUpgradeabilityProxy
                 * @dev This contract combines an upgradeability proxy with an authorization
                 * mechanism for administrative tasks.
                 * All external functions in this contract must be guarded by the
                 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                 * feature proposal that would enable this to be done automatically.
                 */
                contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                    /**
                     * @dev Emitted when the administration has been transferred.
                     * @param previousAdmin Address of the previous admin.
                     * @param newAdmin Address of the new admin.
                     */
                    event AdminChanged(address previousAdmin, address newAdmin);
                
                    /**
                     * @dev Storage slot with the admin of the contract.
                     * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                     * validated in the constructor.
                     */
                    bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                
                    /**
                     * @dev Modifier to check whether the `msg.sender` is the admin.
                     * If it is, it will run the function. Otherwise, it will delegate the call
                     * to the implementation.
                     */
                    modifier ifAdmin() {
                        if (msg.sender == _admin()) {
                            _;
                        } else {
                            _fallback();
                        }
                    }
                
                    /**
                     * Contract constructor.
                     * It sets the `msg.sender` as the proxy administrator.
                     * @param _implementation address of the initial implementation.
                     */
                    constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
                        assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                
                        _setAdmin(msg.sender);
                    }
                
                    /**
                     * @return The address of the proxy admin.
                     */
                    function admin() external view ifAdmin returns (address) {
                        return _admin();
                    }
                
                    /**
                     * @return The address of the implementation.
                     */
                    function implementation() external view ifAdmin returns (address) {
                        return _implementation();
                    }
                
                    /**
                     * @dev Changes the admin of the proxy.
                     * Only the current admin can call this function.
                     * @param newAdmin Address to transfer proxy administration to.
                     */
                    function changeAdmin(address newAdmin) external ifAdmin {
                        require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                        emit AdminChanged(_admin(), newAdmin);
                        _setAdmin(newAdmin);
                    }
                
                    /**
                     * @dev Upgrade the backing implementation of the proxy.
                     * Only the admin can call this function.
                     * @param newImplementation Address of the new implementation.
                     */
                    function upgradeTo(address newImplementation) external ifAdmin {
                        _upgradeTo(newImplementation);
                    }
                
                    /**
                     * @dev Upgrade the backing implementation of the proxy and call a function
                     * on the new implementation.
                     * This is useful to initialize the proxied contract.
                     * @param newImplementation Address of the new implementation.
                     * @param data Data to send as msg.data in the low level call.
                     * It should include the signature and the parameters of the function to be
                     * called, as described in
                     * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
                     */
                    function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                        _upgradeTo(newImplementation);
                        require(address(this).call.value(msg.value)(data));
                    }
                
                    /**
                     * @return The admin slot.
                     */
                    function _admin() internal view returns (address adm) {
                        bytes32 slot = ADMIN_SLOT;
                        assembly {
                            adm := sload(slot)
                        }
                    }
                
                    /**
                     * @dev Sets the address of the proxy admin.
                     * @param newAdmin Address of the new proxy admin.
                     */
                    function _setAdmin(address newAdmin) internal {
                        bytes32 slot = ADMIN_SLOT;
                
                        assembly {
                            sstore(slot, newAdmin)
                        }
                    }
                
                    /**
                     * @dev Only fall back when the sender is not the admin.
                     */
                    function _willFallback() internal {
                        require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                        super._willFallback();
                    }
                }

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

                File 4 of 4: PAXGImplementation
                // File: contracts/zeppelin/SafeMath.sol
                
                pragma solidity 0.4.24;
                
                
                /**
                 * @title SafeMath
                 * @dev Math operations with safety checks that throw on error
                 */
                library SafeMath {
                    /**
                    * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
                    */
                    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                        require(b <= a);
                        uint256 c = a - b;
                
                        return c;
                    }
                
                    /**
                    * @dev Adds two numbers, reverts on overflow.
                    */
                    function add(uint256 a, uint256 b) internal pure returns (uint256) {
                        uint256 c = a + b;
                        require(c >= a);
                
                        return c;
                    }
                
                    /**
                    * @dev Multiplies two unsigned integers, reverts on overflow.
                    */
                    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                        // benefit is lost if 'b' is also tested.
                        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
                        if (a == 0) {
                            return 0;
                        }
                
                        uint256 c = a * b;
                        require(c / a == b);
                
                        return c;
                    }
                
                    /**
                    * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
                    */
                    function div(uint256 a, uint256 b) internal pure returns (uint256) {
                        // Solidity only automatically asserts when dividing by 0
                        require(b > 0);
                        uint256 c = a / b;
                        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                
                        return c;
                    }
                }
                
                // File: contracts/PAXGImplementation.sol
                
                pragma solidity 0.4.24;
                pragma experimental "v0.5.0";
                
                
                
                /**
                 * @title PAXGImplementation
                 * @dev this contract is a Pausable ERC20 token with Burn and Mint
                 * controlled by a central SupplyController. By implementing PaxosImplementation
                 * this contract also includes external methods for setting
                 * a new implementation contract for the Proxy.
                 * NOTE: The storage defined here will actually be held in the Proxy
                 * contract and all calls to this contract should be made through
                 * the proxy, including admin actions done as owner or supplyController.
                 * Any call to transfer against this contract should fail
                 * with insufficient funds since no tokens will be issued there.
                 */
                contract PAXGImplementation {
                
                    /**
                     * MATH
                     */
                
                    using SafeMath for uint256;
                
                    /**
                     * DATA
                     */
                
                    // INITIALIZATION DATA
                    bool private initialized = false;
                
                    // ERC20 BASIC DATA
                    mapping(address => uint256) internal balances;
                    uint256 internal totalSupply_;
                    string public constant name = "Paxos Gold"; // solium-disable-line
                    string public constant symbol = "PAXG"; // solium-disable-line uppercase
                    uint8 public constant decimals = 18; // solium-disable-line uppercase
                
                    // ERC20 DATA
                    mapping(address => mapping(address => uint256)) internal allowed;
                
                    // OWNER DATA
                    address public owner;
                    address public proposedOwner;
                
                    // PAUSABILITY DATA
                    bool public paused = false;
                
                    // ASSET PROTECTION DATA
                    address public assetProtectionRole;
                    mapping(address => bool) internal frozen;
                
                    // SUPPLY CONTROL DATA
                    address public supplyController;
                
                    // DELEGATED TRANSFER DATA
                    address public betaDelegateWhitelister;
                    mapping(address => bool) internal betaDelegateWhitelist;
                    mapping(address => uint256) internal nextSeqs;
                    // EIP191 header for EIP712 prefix
                    string constant internal EIP191_HEADER = "\x19\x01";
                    // Hash of the EIP712 Domain Separator Schema
                    bytes32 constant internal EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(
                        "EIP712Domain(string name,address verifyingContract)"
                    );
                    bytes32 constant internal EIP712_DELEGATED_TRANSFER_SCHEMA_HASH = keccak256(
                        "BetaDelegatedTransfer(address to,uint256 value,uint256 serviceFee,uint256 seq,uint256 deadline)"
                    );
                    // Hash of the EIP712 Domain Separator data
                    // solhint-disable-next-line var-name-mixedcase
                    bytes32 public EIP712_DOMAIN_HASH;
                
                    // FEE CONTROLLER DATA
                    // fee decimals is only set for informational purposes.
                    // 1 feeRate = .000001 oz of gold
                    uint8 public constant feeDecimals = 6;
                
                    // feeRate is measured in 100th of a basis point (parts per 1,000,000)
                    // ex: a fee rate of 200 = 0.02% of an oz of gold
                    uint256 public constant feeParts = 1000000;
                    uint256 public feeRate;
                    address public feeController;
                    address public feeRecipient;
                
                    /**
                     * EVENTS
                     */
                
                    // ERC20 BASIC EVENTS
                    event Transfer(address indexed from, address indexed to, uint256 value);
                
                    // ERC20 EVENTS
                    event Approval(
                        address indexed owner,
                        address indexed spender,
                        uint256 value
                    );
                
                    // OWNABLE EVENTS
                    event OwnershipTransferProposed(
                        address indexed currentOwner,
                        address indexed proposedOwner
                    );
                    event OwnershipTransferDisregarded(
                        address indexed oldProposedOwner
                    );
                    event OwnershipTransferred(
                        address indexed oldOwner,
                        address indexed newOwner
                    );
                
                    // PAUSABLE EVENTS
                    event Pause();
                    event Unpause();
                
                    // ASSET PROTECTION EVENTS
                    event AddressFrozen(address indexed addr);
                    event AddressUnfrozen(address indexed addr);
                    event FrozenAddressWiped(address indexed addr);
                    event AssetProtectionRoleSet (
                        address indexed oldAssetProtectionRole,
                        address indexed newAssetProtectionRole
                    );
                
                    // SUPPLY CONTROL EVENTS
                    event SupplyIncreased(address indexed to, uint256 value);
                    event SupplyDecreased(address indexed from, uint256 value);
                    event SupplyControllerSet(
                        address indexed oldSupplyController,
                        address indexed newSupplyController
                    );
                
                    // DELEGATED TRANSFER EVENTS
                    event BetaDelegatedTransfer(
                        address indexed from, address indexed to, uint256 value, uint256 seq, uint256 serviceFee
                    );
                    event BetaDelegateWhitelisterSet(
                        address indexed oldWhitelister,
                        address indexed newWhitelister
                    );
                    event BetaDelegateWhitelisted(address indexed newDelegate);
                    event BetaDelegateUnwhitelisted(address indexed oldDelegate);
                
                    // FEE CONTROLLER EVENTS
                    event FeeCollected(address indexed from, address indexed to, uint256 value);
                    event FeeRateSet(
                        uint256 indexed oldFeeRate,
                        uint256 indexed newFeeRate
                    );
                    event FeeControllerSet(
                        address indexed oldFeeController,
                        address indexed newFeeController
                    );
                    event FeeRecipientSet(
                        address indexed oldFeeRecipient,
                        address indexed newFeeRecipient
                    );
                
                    /**
                     * FUNCTIONALITY
                     */
                
                    // INITIALIZATION FUNCTIONALITY
                
                    /**
                     * @dev sets 0 initial tokens, the owner, the supplyController,
                     * the fee controller and fee recipient.
                     * this serves as the constructor for the proxy but compiles to the
                     * memory model of the Implementation contract.
                     */
                    function initialize() public {
                        require(!initialized, "already initialized");
                        owner = msg.sender;
                        proposedOwner = address(0);
                        assetProtectionRole = address(0);
                        totalSupply_ = 0;
                        supplyController = msg.sender;
                        feeRate = 0;
                        feeController = msg.sender;
                        feeRecipient = msg.sender;
                        initializeDomainSeparator();
                        initialized = true;
                    }
                
                    /**
                     * The constructor is used here to ensure that the implementation
                     * contract is initialized. An uncontrolled implementation
                     * contract might lead to misleading state
                     * for users who accidentally interact with it.
                     */
                    constructor() public {
                        initialize();
                        pause();
                    }
                
                    /**
                     * @dev To be called when upgrading the contract using upgradeAndCall to add delegated transfers
                     */
                    function initializeDomainSeparator() public {
                        // hash the name context with the contract address
                        EIP712_DOMAIN_HASH = keccak256(abi.encodePacked(// solium-disable-line
                                EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
                                keccak256(bytes(name)),
                                bytes32(address(this))
                            ));
                    }
                
                    // ERC20 BASIC FUNCTIONALITY
                
                    /**
                    * @dev Total number of tokens in existence
                    */
                    function totalSupply() public view returns (uint256) {
                        return totalSupply_;
                    }
                
                    /**
                    * @dev Transfer token to a specified address from msg.sender
                    * Transfer additionally sends the fee to the fee controller
                    * Note: the use of Safemath ensures that _value is nonnegative.
                    * @param _to The address to transfer to.
                    * @param _value The amount to be transferred.
                    */
                    function transfer(address _to, uint256 _value) public whenNotPaused returns (bool) {
                        require(_to != address(0), "cannot transfer to address zero");
                        require(!frozen[_to] && !frozen[msg.sender], "address frozen");
                        require(_value <= balances[msg.sender], "insufficient funds");
                
                        _transfer(msg.sender, _to, _value);
                        return true;
                    }
                
                    /**
                    * @dev Gets the balance of the specified address.
                    * @param _addr The address to query the the balance of.
                    * @return An uint256 representing the amount owned by the passed address.
                    */
                    function balanceOf(address _addr) public view returns (uint256) {
                        return balances[_addr];
                    }
                
                    // ERC20 FUNCTIONALITY
                
                    /**
                     * @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 uint256 the amount of tokens to be transferred
                     */
                    function transferFrom(
                        address _from,
                        address _to,
                        uint256 _value
                    )
                    public
                    whenNotPaused
                    returns (bool)
                    {
                        require(_to != address(0), "cannot transfer to address zero");
                        require(!frozen[_to] && !frozen[_from] && !frozen[msg.sender], "address frozen");
                        require(_value <= balances[_from], "insufficient funds");
                        require(_value <= allowed[_from][msg.sender], "insufficient allowance");
                
                        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
                        _transfer(_from, _to, _value);
                
                        return true;
                    }
                
                    /**
                     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
                     * 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
                     * @param _spender The address which will spend the funds.
                     * @param _value The amount of tokens to be spent.
                     */
                    function approve(address _spender, uint256 _value) public whenNotPaused returns (bool) {
                        require(!frozen[_spender] && !frozen[msg.sender], "address frozen");
                        allowed[msg.sender][_spender] = _value;
                        emit Approval(msg.sender, _spender, _value);
                        return true;
                    }
                
                    /**
                     * @dev Function to check the amount of tokens that 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 uint256 specifying the amount of tokens still available for the spender.
                     */
                    function allowance(
                        address _owner,
                        address _spender
                    )
                    public
                    view
                    returns (uint256)
                    {
                        return allowed[_owner][_spender];
                    }
                
                    function _transfer(address _from, address _to, uint256 _value) internal returns (uint256) {
                        uint256 _fee = getFeeFor(_value);
                        uint256 _principle = _value.sub(_fee);
                        balances[_from] = balances[_from].sub(_value);
                        balances[_to] = balances[_to].add(_principle);
                        emit Transfer(_from, _to, _principle);
                        emit Transfer(_from, feeRecipient, _fee);
                        if (_fee > 0) {
                            balances[feeRecipient] = balances[feeRecipient].add(_fee);
                            emit FeeCollected(_from, feeRecipient, _fee);
                        }
                
                        return _principle;
                    }
                
                    // OWNER FUNCTIONALITY
                
                    /**
                     * @dev Throws if called by any account other than the owner.
                     */
                    modifier onlyOwner() {
                        require(msg.sender == owner, "onlyOwner");
                        _;
                    }
                
                    /**
                     * @dev Allows the current owner to begin transferring control of the contract to a proposedOwner
                     * @param _proposedOwner The address to transfer ownership to.
                     */
                    function proposeOwner(address _proposedOwner) public onlyOwner {
                        require(_proposedOwner != address(0), "cannot transfer ownership to address zero");
                        require(msg.sender != _proposedOwner, "caller already is owner");
                        proposedOwner = _proposedOwner;
                        emit OwnershipTransferProposed(owner, proposedOwner);
                    }
                
                    /**
                     * @dev Allows the current owner or proposed owner to cancel transferring control of the contract to a proposedOwner
                     */
                    function disregardProposeOwner() public {
                        require(msg.sender == proposedOwner || msg.sender == owner, "only proposedOwner or owner");
                        require(proposedOwner != address(0), "can only disregard a proposed owner that was previously set");
                        address _oldProposedOwner = proposedOwner;
                        proposedOwner = address(0);
                        emit OwnershipTransferDisregarded(_oldProposedOwner);
                    }
                
                    /**
                     * @dev Allows the proposed owner to complete transferring control of the contract to the proposedOwner.
                     */
                    function claimOwnership() public {
                        require(msg.sender == proposedOwner, "onlyProposedOwner");
                        address _oldOwner = owner;
                        owner = proposedOwner;
                        proposedOwner = address(0);
                        emit OwnershipTransferred(_oldOwner, owner);
                    }
                
                    /**
                     * @dev Reclaim all PAXG at the contract address.
                     * This sends the PAXG tokens that this contract add holding to the owner.
                     * Note: this is not affected by freeze constraints.
                     */
                    function reclaimPAXG() external onlyOwner {
                        uint256 _balance = balances[this];
                        balances[this] = 0;
                        balances[owner] = balances[owner].add(_balance);
                        emit Transfer(this, owner, _balance);
                    }
                
                    // PAUSABILITY FUNCTIONALITY
                
                    /**
                     * @dev Modifier to make a function callable only when the contract is not paused.
                     */
                    modifier whenNotPaused() {
                        require(!paused, "whenNotPaused");
                        _;
                    }
                
                    /**
                     * @dev called by the owner to pause, triggers stopped state
                     */
                    function pause() public onlyOwner {
                        require(!paused, "already paused");
                        paused = true;
                        emit Pause();
                    }
                
                    /**
                     * @dev called by the owner to unpause, returns to normal state
                     */
                    function unpause() public onlyOwner {
                        require(paused, "already unpaused");
                        paused = false;
                        emit Unpause();
                    }
                
                    // ASSET PROTECTION FUNCTIONALITY
                
                    /**
                     * @dev Sets a new asset protection role address.
                     * @param _newAssetProtectionRole The new address allowed to freeze/unfreeze addresses and seize their tokens.
                     */
                    function setAssetProtectionRole(address _newAssetProtectionRole) public {
                        require(msg.sender == assetProtectionRole || msg.sender == owner, "only assetProtectionRole or Owner");
                        emit AssetProtectionRoleSet(assetProtectionRole, _newAssetProtectionRole);
                        assetProtectionRole = _newAssetProtectionRole;
                    }
                
                    modifier onlyAssetProtectionRole() {
                        require(msg.sender == assetProtectionRole, "onlyAssetProtectionRole");
                        _;
                    }
                
                    /**
                     * @dev Freezes an address balance from being transferred.
                     * @param _addr The new address to freeze.
                     */
                    function freeze(address _addr) public onlyAssetProtectionRole {
                        require(!frozen[_addr], "address already frozen");
                        frozen[_addr] = true;
                        emit AddressFrozen(_addr);
                    }
                
                    /**
                     * @dev Unfreezes an address balance allowing transfer.
                     * @param _addr The new address to unfreeze.
                     */
                    function unfreeze(address _addr) public onlyAssetProtectionRole {
                        require(frozen[_addr], "address already unfrozen");
                        frozen[_addr] = false;
                        emit AddressUnfrozen(_addr);
                    }
                
                    /**
                     * @dev Wipes the balance of a frozen address, burning the tokens
                     * and setting the approval to zero.
                     * @param _addr The new frozen address to wipe.
                     */
                    function wipeFrozenAddress(address _addr) public onlyAssetProtectionRole {
                        require(frozen[_addr], "address is not frozen");
                        uint256 _balance = balances[_addr];
                        balances[_addr] = 0;
                        totalSupply_ = totalSupply_.sub(_balance);
                        emit FrozenAddressWiped(_addr);
                        emit SupplyDecreased(_addr, _balance);
                        emit Transfer(_addr, address(0), _balance);
                    }
                
                    /**
                    * @dev Gets whether the address is currently frozen.
                    * @param _addr The address to check if frozen.
                    * @return A bool representing whether the given address is frozen.
                    */
                    function isFrozen(address _addr) public view returns (bool) {
                        return frozen[_addr];
                    }
                
                    // SUPPLY CONTROL FUNCTIONALITY
                
                    /**
                     * @dev Sets a new supply controller address.
                     * @param _newSupplyController The address allowed to burn/mint tokens to control supply.
                     */
                    function setSupplyController(address _newSupplyController) public {
                        require(msg.sender == supplyController || msg.sender == owner, "only SupplyController or Owner");
                        require(_newSupplyController != address(0), "cannot set supply controller to address zero");
                        emit SupplyControllerSet(supplyController, _newSupplyController);
                        supplyController = _newSupplyController;
                    }
                
                    modifier onlySupplyController() {
                        require(msg.sender == supplyController, "onlySupplyController");
                        _;
                    }
                
                    /**
                     * @dev Increases the total supply by minting the specified number of tokens to the supply controller account.
                     * @param _value The number of tokens to add.
                     * @return A boolean that indicates if the operation was successful.
                     */
                    function increaseSupply(uint256 _value) public onlySupplyController returns (bool success) {
                        totalSupply_ = totalSupply_.add(_value);
                        balances[supplyController] = balances[supplyController].add(_value);
                        emit SupplyIncreased(supplyController, _value);
                        emit Transfer(address(0), supplyController, _value);
                        return true;
                    }
                
                    /**
                     * @dev Decreases the total supply by burning the specified number of tokens from the supply controller account.
                     * @param _value The number of tokens to remove.
                     * @return A boolean that indicates if the operation was successful.
                     */
                    function decreaseSupply(uint256 _value) public onlySupplyController returns (bool success) {
                        require(_value <= balances[supplyController], "not enough supply");
                        balances[supplyController] = balances[supplyController].sub(_value);
                        totalSupply_ = totalSupply_.sub(_value);
                        emit SupplyDecreased(supplyController, _value);
                        emit Transfer(supplyController, address(0), _value);
                        return true;
                    }
                
                    // DELEGATED TRANSFER FUNCTIONALITY
                
                    /**
                     * @dev returns the next seq for a target address.
                     * The transactor must submit nextSeqOf(transactor) in the next transaction for it to be valid.
                     * Note: that the seq context is specific to this smart contract.
                     * @param target The target address.
                     * @return the seq.
                     */
                    //
                    function nextSeqOf(address target) public view returns (uint256) {
                        return nextSeqs[target];
                    }
                
                    /**
                     * @dev Performs a transfer on behalf of the from address, identified by its signature on the delegatedTransfer msg.
                     * Splits a signature byte array into r,s,v for convenience.
                     * @param sig the signature of the delgatedTransfer msg.
                     * @param to The address to transfer to.
                     * @param value The amount to be transferred.
                     * @param serviceFee an optional ERC20 service fee paid to the executor of betaDelegatedTransfer by the from address.
                     * @param seq a sequencing number included by the from address specific to this contract to protect from replays.
                     * @param deadline a block number after which the pre-signed transaction has expired.
                     * @return A boolean that indicates if the operation was successful.
                     */
                    function betaDelegatedTransfer(
                        bytes sig, address to, uint256 value, uint256 serviceFee, uint256 seq, uint256 deadline
                    ) public returns (bool) {
                        require(sig.length == 65, "signature should have length 65");
                        bytes32 r;
                        bytes32 s;
                        uint8 v;
                        assembly {
                            r := mload(add(sig, 32))
                            s := mload(add(sig, 64))
                            v := byte(0, mload(add(sig, 96)))
                        }
                        require(_betaDelegatedTransfer(r, s, v, to, value, serviceFee, seq, deadline), "failed transfer");
                        return true;
                    }
                
                    /**
                     * @dev Performs a transfer on behalf of the from address, identified by its signature on the betaDelegatedTransfer msg.
                     * Note: both the delegate and transactor sign in the service fees. The transactor, however,
                     * has no control over the gas price, and therefore no control over the transaction time.
                     * Beta prefix chosen to avoid a name clash with an emerging standard in ERC865 or elsewhere.
                     * Internal to the contract - see betaDelegatedTransfer and betaDelegatedTransferBatch.
                     * @param r the r signature of the delgatedTransfer msg.
                     * @param s the s signature of the delgatedTransfer msg.
                     * @param v the v signature of the delgatedTransfer msg.
                     * @param to The address to transfer to.
                     * @param value The amount to be transferred.
                     * @param serviceFee an optional ERC20 service fee paid to the delegate of betaDelegatedTransfer by the from address.
                     * @param seq a sequencing number included by the from address specific to this contract to protect from replays.
                     * @param deadline a block number after which the pre-signed transaction has expired.
                     * @return A boolean that indicates if the operation was successful.
                     */
                    function _betaDelegatedTransfer(
                        bytes32 r, bytes32 s, uint8 v, address to, uint256 value, uint256 serviceFee, uint256 seq, uint256 deadline
                    ) internal whenNotPaused returns (bool) {
                        require(betaDelegateWhitelist[msg.sender], "Beta feature only accepts whitelisted delegates");
                        require(value > 0 || serviceFee > 0, "cannot transfer zero tokens with zero service fee");
                        require(block.number <= deadline, "transaction expired");
                        // prevent sig malleability from ecrecover()
                        require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "signature incorrect");
                        require(v == 27 || v == 28, "signature incorrect");
                
                        // EIP712 scheme: https://github.com/ethereum/EIPs/blob/master/EIPS/eip-712.md
                        bytes32 hash = keccak256(abi.encodePacked(EIP191_HEADER, EIP712_DOMAIN_HASH, keccak256(abi.encodePacked(// solium-disable-line
                                EIP712_DELEGATED_TRANSFER_SCHEMA_HASH, bytes32(to), value, serviceFee, seq, deadline
                        ))));
                        address _from = ecrecover(hash, v, r, s);
                
                        require(_from != address(0), "error determining from address from signature");
                        require(to != address(0), "cannot use address zero");
                        require(!frozen[to] && !frozen[_from] && !frozen[msg.sender], "address frozen");
                        require(value.add(serviceFee) <= balances[_from], "insufficient funds or bad signature");
                        require(nextSeqs[_from] == seq, "incorrect seq");
                
                        nextSeqs[_from] = nextSeqs[_from].add(1);
                
                        uint256 _principle = _transfer(_from, to, value);
                
                        if (serviceFee != 0) {
                            balances[_from] = balances[_from].sub(serviceFee);
                            balances[msg.sender] = balances[msg.sender].add(serviceFee);
                            emit Transfer(_from, msg.sender, serviceFee);
                        }
                
                        emit BetaDelegatedTransfer(_from, to, _principle, seq, serviceFee);
                        return true;
                    }
                
                    /**
                     * @dev Performs an atomic batch of transfers on behalf of the from addresses, identified by their signatures.
                     * Lack of nested array support in arguments requires all arguments to be passed as equal size arrays where
                     * delegated transfer number i is the combination of all arguments at index i
                     * @param r the r signatures of the delgatedTransfer msg.
                     * @param s the s signatures of the delgatedTransfer msg.
                     * @param v the v signatures of the delgatedTransfer msg.
                     * @param to The addresses to transfer to.
                     * @param value The amounts to be transferred.
                     * @param serviceFee optional ERC20 service fees paid to the delegate of betaDelegatedTransfer by the from address.
                     * @param seq sequencing numbers included by the from address specific to this contract to protect from replays.
                     * @param deadline block numbers after which the pre-signed transactions have expired.
                     * @return A boolean that indicates if the operation was successful.
                     */
                    function betaDelegatedTransferBatch(
                        bytes32[] r, bytes32[] s, uint8[] v, address[] to, uint256[] value, uint256[] serviceFee, uint256[] seq, uint256[] deadline
                    ) public returns (bool) {
                        require(r.length == s.length && r.length == v.length && r.length == to.length && r.length == value.length, "length mismatch");
                        require(r.length == serviceFee.length && r.length == seq.length && r.length == deadline.length, "length mismatch");
                
                        for (uint i = 0; i < r.length; i++) {
                            require(
                                _betaDelegatedTransfer(r[i], s[i], v[i], to[i], value[i], serviceFee[i], seq[i], deadline[i]),
                                "failed transfer"
                            );
                        }
                        return true;
                    }
                
                    /**
                    * @dev Gets whether the address is currently whitelisted for betaDelegateTransfer.
                    * @param _addr The address to check if whitelisted.
                    * @return A bool representing whether the given address is whitelisted.
                    */
                    function isWhitelistedBetaDelegate(address _addr) public view returns (bool) {
                        return betaDelegateWhitelist[_addr];
                    }
                
                    /**
                     * @dev Sets a new betaDelegate whitelister.
                     * @param _newWhitelister The address allowed to whitelist betaDelegates.
                     */
                    function setBetaDelegateWhitelister(address _newWhitelister) public {
                        require(msg.sender == betaDelegateWhitelister || msg.sender == owner, "only Whitelister or Owner");
                        betaDelegateWhitelister = _newWhitelister;
                        emit BetaDelegateWhitelisterSet(betaDelegateWhitelister, _newWhitelister);
                    }
                
                    modifier onlyBetaDelegateWhitelister() {
                        require(msg.sender == betaDelegateWhitelister, "onlyBetaDelegateWhitelister");
                        _;
                    }
                
                    /**
                     * @dev Whitelists an address to allow calling BetaDelegatedTransfer.
                     * @param _addr The new address to whitelist.
                     */
                    function whitelistBetaDelegate(address _addr) public onlyBetaDelegateWhitelister {
                        require(!betaDelegateWhitelist[_addr], "delegate already whitelisted");
                        betaDelegateWhitelist[_addr] = true;
                        emit BetaDelegateWhitelisted(_addr);
                    }
                
                    /**
                     * @dev Unwhitelists an address to disallow calling BetaDelegatedTransfer.
                     * @param _addr The new address to whitelist.
                     */
                    function unwhitelistBetaDelegate(address _addr) public onlyBetaDelegateWhitelister {
                        require(betaDelegateWhitelist[_addr], "delegate not whitelisted");
                        betaDelegateWhitelist[_addr] = false;
                        emit BetaDelegateUnwhitelisted(_addr);
                    }
                
                    // FEE CONTROLLER FUNCTIONALITY
                
                    /**
                     * @dev Sets a new fee controller address.
                     * @param _newFeeController The address allowed to set the fee rate and the fee recipient.
                     */
                    function setFeeController(address _newFeeController) public {
                        require(msg.sender == feeController || msg.sender == owner, "only FeeController or Owner");
                        require(_newFeeController != address(0), "cannot set fee controller to address zero");
                        address _oldFeeController = feeController;
                        feeController = _newFeeController;
                        emit FeeControllerSet(_oldFeeController, feeController);
                    }
                
                    modifier onlyFeeController() {
                        require(msg.sender == feeController, "only FeeController");
                        _;
                    }
                
                    /**
                     * @dev Sets a new fee recipient address.
                     * @param _newFeeRecipient The address allowed to collect transfer fees for transfers.
                     */
                    function setFeeRecipient(address _newFeeRecipient) public onlyFeeController {
                        require(_newFeeRecipient != address(0), "cannot set fee recipient to address zero");
                        address _oldFeeRecipient = feeRecipient;
                        feeRecipient = _newFeeRecipient;
                        emit FeeRecipientSet(_oldFeeRecipient, feeRecipient);
                    }
                
                    /**
                     * @dev Sets a new fee rate.
                     * @param _newFeeRate The new fee rate to collect as transfer fees for transfers.
                     */
                    function setFeeRate(uint256 _newFeeRate) public onlyFeeController {
                        require(_newFeeRate <= feeParts, "cannot set fee rate above 100%");
                        uint256 _oldFeeRate = feeRate;
                        feeRate = _newFeeRate;
                        emit FeeRateSet(_oldFeeRate, feeRate);
                    }
                
                    /**
                    * @dev Gets a fee for a given value
                    * ex: given feeRate = 200 and feeParts = 1,000,000 then getFeeFor(10000) = 2
                    * @param _value The amount to get the fee for.
                    */
                    function getFeeFor(uint256 _value) public view returns (uint256) {
                        if (feeRate == 0) {
                            return 0;
                        }
                
                        return _value.mul(feeRate).div(feeParts);
                    }
                }