@exodus/bip322-js/dist/helpers/BIP137.js

A Javascript library that provides utility functions related to the BIP-322 signature scheme

import * as bitcoinMessage from '@exodus/bitcoinjs/message';
import { recoverPublicKey } from '@noble/secp256k1';
class BIP137 {
    static isBIP137Signature(signature) {
        return signature.byteLength === 65;
    }
    static derivePubKey(message, signature) {
        const messageHash = bitcoinMessage.magicHash(message);
        const signatureDecoded = this.decodeSignature(signature);
        const recoveredPublicKey = recoverPublicKey(messageHash, signatureDecoded.signature, signatureDecoded.recovery, signatureDecoded.compressed);
        return Buffer.from(recoveredPublicKey);
    }
    static decodeSignature(signature) {
        if (signature.length !== 65)
            throw new Error('Invalid signature length');
        const flagByte = signature.readUInt8(0) - 27;
        if (flagByte > 19 || flagByte < 0) {
            throw new Error('Invalid signature parameter');
        }
        return {
            compressed: !!(flagByte & 12),
            recovery: flagByte & 3,
            signature: signature.subarray(1),
        };
    }
}
export default BIP137;