verify method

@override FutureOr<bool> verify(String jws, { String? did, Map<String, dynamic>? jwk, dynamic data, })

Verifies a (detached) JWS

Implementation

@override
FutureOr<bool> verify(String jws,
    {String? did, Map<String, dynamic>? jwk, dynamic data}) async {
  Map<String, dynamic> signingKey;
  if (did != null) {
    var ddo =
        (await resolveDidDocument(did)).resolveKeyIds().convertAllKeysToJwk();
    signingKey = ddo.verificationMethod!.first.publicKeyJwk!;
  } else if (jwk != null) {
    signingKey = jwk;
  } else {
    throw Exception('Either did or jwk must be given');
  }

  var splitted = jws.split('.');
  if (splitted.length != 3) throw Exception('maleformed jws');

  String encodedPayload;
  if (data != null) {
    encodedPayload = data is String
        ? removePaddingFromBase64(base64UrlEncode(utf8.encode(data)))
        : removePaddingFromBase64(
            base64UrlEncode(utf8.encode(jsonEncode(credentialToMap(data)))));
  } else {
    encodedPayload = splitted[1];
  }

  var signingInput = '${splitted[0]}.$encodedPayload';

  var pubKey = EcPublicKey(
      xCoordinate: web3_crypto.bytesToUnsignedInt(
          base64Decode(addPaddingToBase64(signingKey['x']))),
      yCoordinate: web3_crypto.bytesToUnsignedInt(
          base64Decode(addPaddingToBase64(signingKey['y']))),
      curve: curves.p256k);
  var verifier = pubKey.createVerifier(algorithms.signing.ecdsa.sha256);

  return verifier.verify(ascii.encode(signingInput),
      Signature(base64Decode(addPaddingToBase64(splitted[2]))));
}