verify function
Implementation
bool verify(String message, Uint8List signature, Secp256k1PublicKey publicKey) {
final blob = message.plainToU8a(useDartEncode: true);
final digest = SHA256Digest();
final signer = ECDSASigner(digest, HMac(digest, 64));
var sig = ECSignature(signature.sublist(0, 32).toBn(endian: Endian.big),
signature.sublist(32).toBn(endian: Endian.big));
var kpub = params.curve.decodePoint(publicKey.toRaw())!;
var pub = ECPublicKey(kpub, params);
signer.init(false, p_api.PublicKeyParameter(pub));
return signer.verifySignature(blob, sig);
}