EIP712 WROSE

WROSE.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";

contract VerifyTypedData {
    using ECDSA for bytes32;

    /*
     * @param   _signature =    0xb066103c3fe76389334e2df744caa60d61b2e52f57ea1c3569941558ae8a43a03312ed2e3326bcbea6af812cb50e0e1c8fad12bdfdde60f9459b634674c86dbc1b
     * @parm    _to =           0xdD4c825203f97984e7867F11eeCc813A036089D1
     * @param   _value =        123
     * @param   _nonce =        1
     * @return  address =       0xdD4c825203f97984e7867F11eeCc813A036089D1
     */
    function getSigner(bytes memory _signature, address _to,uint256 _value,uint256 _nonce,uint256 _reward)
        public
        view
        returns (address)
    {
        // EIP721 domain type
        string memory name = "WROSE";
        string memory version = "1";
        uint256 chainId = 42262;
        address verifyingContract = address(this); // 0x0000000000000000000000000000000000000000;

        // stringified types
        string memory EIP712_DOMAIN_TYPE = "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)";
        string memory MESSAGE_TYPE = "Message(address to,uint256 value,uint256 nonce,uint256 reward)";

        // hash to prevent signature collision
        bytes32 DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256(abi.encodePacked(EIP712_DOMAIN_TYPE)),
                keccak256(abi.encodePacked(name)),
                keccak256(abi.encodePacked(version)),
                chainId,
                verifyingContract
            )
        );

        // hash typed data
        bytes32 hash = keccak256(
            abi.encodePacked(
                "\x19\x01", // backslash is needed to escape the character
                DOMAIN_SEPARATOR,
                keccak256(
                    abi.encode(
                        keccak256(abi.encodePacked(MESSAGE_TYPE)),
                        _to,_value,_nonce,_reward // _myValue 
                    )
                )
            )
        );

        return hash.recover(_signature);
    }
}


/**

<script>
  // https://docs.metamask.io/guide/signing-data.html#sign-typed-data-v4
(async function () {
    // connect to wallet
    const from = await ethereum.request({ method: "eth_requestAccounts" });

    const msgParams = JSON.stringify({
    domain: {
        // Give a user friendly name to the specific contract you are signing for.
        name: "WROSE", // "MyName"
        // Just let's you know the latest version. Definitely make sure the field name is correct.
        version: "1", // "1"
        // Defining the chain aka Rinkeby testnet or Ethereum Main Net
        chainId: 42262, // 1
        // If name isn't enough add verifying contract to make sure you are establishing contracts with the proper entity
        verifyingContract: "0x0000000000000000000000000000000000000000"// "0x0000000000000000000000000000000000000000",
    },

    // Defining the message signing data content.
    message: {
        to: "0xdD4c825203f97984e7867F11eeCc813A036089D1",value: 123,nonce: 1,reward: 123123,
    },
    // Refers to the keys of the *types* object below.
    primaryType: "Message",
    types: {
        EIP712Domain: [
        { name: "name", type: "string" },
        { name: "version", type: "string" },
        { name: "chainId", type: "uint256" },
        { name: "verifyingContract", type: "address" },
        ],
        // Refer to primaryType
        Message: [{"name":"to","type":"address"},{"name":"value","type":"uint256"},{"name":"nonce","type":"uint256"},{"name":"reward","type":"uint256"}] // [{ name: "myValue", type: "uint256" }],
    },
    });

    web3.currentProvider.sendAsync(
        {
            method: "eth_signTypedData_v4",
            params: [from[0], msgParams],
            from: from[0],
        },
        function (err, result) {
            if (err) return console.dir(err);
            if (result.error) {
            alert(result.error.message);
            }
            if (result.error) return console.error("ERROR", result);
            console.log("SIGNATURE:" + JSON.stringify(result.result));
        }
    );
})()

</script>

**/