USDC EIP-3009 Ethereum and Polygon code mismatches

Question

We're implementing gasless transactions and we need eip3009 transfer With Authorisation call. We're interested in USDC.

I see some mismatches in USDC code on ethereum and polygon. To be accurate in domain separator. So, for ethereum I see this:

 function makeDomainSeparator(string memory name, string memory version)
        internal
        view
        returns (bytes32)
    {
        uint256 chainId;
        assembly {
            chainId := chainid()
        }
        return
            keccak256(
                abi.encode(
                    // keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)")
                    0x8b73c3c69bb8fe3d512ecc4cf759cc79239f7b179b0ffacaa9a75d522b39400f,
                    keccak256(bytes(name)),
                    keccak256(bytes(version)),
                    chainId,
                    address(this)
                )
            );
    }

And for polygon:

    function makeDomainSeparator(string memory name, string memory version)
        internal
        view
        returns (bytes32)
    {
        uint256 chainId;
        assembly {
            chainId := chainid()
        }

        return
            keccak256(
                abi.encode(
                    // keccak256("EIP712Domain(string name,string version,address verifyingContract,bytes32 salt)")
                    0x36c25de3e541d5d970f66e4210d728721220fff5c077cc6cd008b3a0c62adab7,
                    keccak256(bytes(name)),
                    keccak256(bytes(version)),
                    address(this),
                    bytes32(chainId)
                )
            );
    }

I use this code to sign this transaction:

const data = {
  types: {
      TransferWithAuthorization: [
          { name: "from", type: "address" },
          { name: "to", type: "address" },
          { name: "value", type: "uint256" },
          { name: "validAfter", type: "uint256" },
          { name: "validBefore", type: "uint256" },
          { name: "nonce", type: "bytes32" },
      ],
  }
  domain: {
    name: 'MockEIP3009Token',
    version: '0.0.1',
    chainId: 31337,
    verifyingContract: '0x1429859428C0aBc9C2C47C8Ee9FBaf82cFA0F20f'
  },
  primaryType: 'TransferWithAuthorization',
  message: {
    from: '0x9965507D1a55bcC2695C58ba16FB37d819B0A4dc',
    to: '0xfd471836031dc5108809d173a067e8486b9047a3',
    value: 434266,
    validAfter: 0,
    validBefore: 1672224083,
    nonce: '0x16140b6e6c12c7538910d7d08e52620f146518af84281a68576bb679b2c1100a'
  }
}
signer._signTypedData(data.domain, data.types, data.message);

For ethereum code everything works fine, but with polygon code I receive invalid signature error.

Can somebody explain why such difference is required?

Contracts:

• ethereum implementation contract: https://etherscan.io/address/0xa2327a938febf5fec13bacfb16ae10ecbc4cbdcf#code
• polygon implementation contract: https://polygonscan.com/address/0xdd9185db084f5c4fff3b4f70e7ba62123b812226#code

Thank you!

Answer 1

Polygon USD Coin (PoS), USDC, or any of bridged Polygon tokens are not EIP-3009 compatible.

They have transferWithAuthorization function, but you need to use a different EIP-712 message for signing. See here for more details.

EIP-3009:

EIP712Domain: [
  { name: 'name', type: 'string' },
  { name: 'version', type: 'string' },
  { name: 'chainId', type: 'uint256' },
  { name: 'verifyingContract', type: 'address' }
]

Polygon:

EIP712Domain: [
  { name: 'name', type: 'string' },
  { name: 'version', type: 'string' },
  { name: 'verifyingContract', type: 'address' },
  { name: 'salt', type: 'bytes32' }
]

Answer 2

Where do you include the TRANSFER_AUTHORIZATION_TYPEHASH in the ethers side of things, like for creating the signature.

There's the struct, that contains the relevant data about the user interaction, but before you domain-hash the struct, it also includes the transfer with authorization typehash, right? I never see that as a value inserted into the struct on the ethers.js side of things.

An example is in here, the EIP3009.sol implementation: https://github.com/ethereum/EIPs/issues/3010#:~:text=Implementation-,EIP3009,-.sol

But within the "Use with web3 providers" example, I don't see the TRANSFER_AUTHORIZATION_TYPEHASH bytes32 included? https://github.com/ethereum/EIPs/issues/3010#:~:text=eth_signTypedData%7B_v4%7D%20method.-,Example,-%3A