verify method

@override bool verify(JWTKey key, Uint8List body, Uint8List signature)

Verify the signature of body with key

return true if the signature is correct false otherwise

Implementation

@override
bool verify(JWTKey key, Uint8List body, Uint8List signature) {
  assert(key is RSAPublicKey, 'key must be a RSAPublicKey');
  final publicKey = key as RSAPublicKey;

  try {
    final algorithm = _getAlgorithm(name);

    final signer = pc.Signer('${_getHash(name)}/${algorithm}');
    pc.CipherParameters params = pc.PublicKeyParameter<pc.RSAPublicKey>(
      publicKey.key,
    );

    if (algorithm == 'PSS') {
      final secureRandom = pc.SecureRandom('Fortuna');
      final random = Random.secure();
      final seed = List.generate(32, (_) => random.nextInt(256));
      secureRandom.seed(pc.KeyParameter(Uint8List.fromList(seed)));

      params = pc.ParametersWithSaltConfiguration(
        params,
        secureRandom,
        32,
      );
    }

    signer.init(false, params);

    final msg = Uint8List.fromList(body);
    final sign = algorithm == 'PSS'
        ? pc.PSSSignature(Uint8List.fromList(signature))
        : pc.RSASignature(Uint8List.fromList(signature));

    return signer.verifySignature(msg, sign);
  } catch (ex) {
    return false;
  }
}