ECDSA Sign off-chain and Validate on-chain

contract.sol

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

using ECDSA for bytes32;
// verify signature
if (
    keccak256(abi.encodePacked(msg.sender, address(this))).toEthSignedMessageHash().recover(signature) !=
    owner()
) revert InvalidSignature();

sign.php

<?php

use Elliptic\EC;
use kornrunner\Keccak;

// all addresses are without 0x

function hashMessage($address, $contractAddress): string
{
    return Keccak::hash(hex2bin($address . $contractAddress), 256);
}

function sign($message, $privateKey): string
{
    $message = Keccak::hash(hex2bin(bin2hex("\x19Ethereum Signed Message:\n32") . $message), 256);

    $ec = new EC('secp256k1');
    $privateKey = $ec->keyFromPrivate($privateKey);
    $signature = $privateKey->sign($message, ['canonical' => true]);
    $r = str_pad($signature->r->toString(16), 64, '0', STR_PAD_LEFT);
    $s = str_pad($signature->s->toString(16), 64, '0', STR_PAD_LEFT);
    $v = dechex($signature->recoveryParam + 27);
    return "0x$r$s$v";
}

function hashAndSign($address, $contractAddress, $privateKey): array
{
    $hash = hashMessage($address, $contractAddress);
    return sign($hash, $privateKey);
}

sign.ts

async function getPreSaleSignature(
  signer: SignerWithAddress,
  minter: SignerWithAddress,
  contractAddress: string
): Promise<string> {

  const hash = ethers.utils.solidityKeccak256(['address', 'address'], [minter.address, contractAddress]);
  return signer.signMessage(ethers.utils.arrayify(hash));
}