danielnordh

var web3 = require("web3");
const ethSigUtil = require("@metamask/eth-sig-util");
const { SignTypedDataVersion } = require("@metamask/eth-sig-util");
const ethUtil = require("ethereumjs-util");

async function permit(_web3, _USDCInstance) {
  const usdcAddress = "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359";
  const privateKey = "..."; // owner's pk
  const pkBuffer = Buffer.from(privateKey, "hex");

danielnordh

final msgParams = {
      "types": {
        "EIP712Domain": [
          {"type": "string", "name": "name"},
          {"type": "string", "name": "version"},
          {"type": "uint256", "name": "chainId"},
          {"type": "address", "name": "verifyingContract"}
        ],
        "TransferWithAuthorization": [
          {"name": "from", "type": "address"},

danielnordh

// See comment below with code example

danielnordh

Future<String?> signUSDC(
      BigInt amount, Web3Dart.EthereumAddress ethAddress, User user) async {
    final config = ref.read(configurationProvider).instance;
    final wallet = Web3Dart.Wallet.fromJson(user.ethereumWallet!, kWalletPassword);

    final validAfter = BigInt.zero;
    final validBefore = BigInt.from(9223372036854775807);
    final nonce = Nonce.secure(32);
    final nonceBytes = utf8.encode(nonce.toString());