[Question] How to derive KeyPair from private key hex?

[Halimao]

I have exported from OKX web3 wallet and got a private key hex string with length 64.

How can I derive my account from this private key hex string?

Image the value of private key string named privKey is a3f1c2d4e5b67890abcdef1234567890abcdef1234567890abcdef1234567890

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I have tried keyPairFromSecretKey and keyPairFromSeed, but both don't work.

const keyPair = keyPairFromSecretKey(Buffer.from(privKey, 'hex'));

this will cause

// Error: bad secret key size
    at nacl.sign.keyPair.fromSecretKey

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keyPairFromSeed(Buffer.from(privKey, 'hex'));
const workchain = 0;
const wallet = WalletContractV4.create({
      workchain,
      publicKey: keyPair.publicKey,
 });
console.log(wallet.address);

This won't cause error, but got a different address from OKX wallet shows.