verify method

@override Future<void> verify(List<int> message, List<int> signature)

Verifies a signature for the provided message using this COSE public key.

Throws an Exception if verification fails or the algorithm is unsupported.

Implementation

@override
Future<void> verify(List<int> message, List<int> signature) async {
  final xBytes = this[CoseKey.okpXIdx] as List<int>?;
  if (xBytes == null) {
    throw Exception('Ed25519 verification failed: missing public key (x).');
  }
  // Ed25519 signatures must be exactly 64 bytes (R || S)
  if (signature.length != 64) {
    throw Exception(
        'Assertion signature verification failed (Ed25519): invalid signature length ${signature.length}, expected 64 bytes.');
  }
  final pubKey = crypto_api.SimplePublicKey(
    xBytes,
    type: crypto_api.KeyPairType.ed25519,
  );
  final verified = await crypto_api.Ed25519().verify(
    message,
    signature: crypto_api.Signature(signature, publicKey: pubKey),
  );
  if (!verified) {
    throw Exception('Assertion signature verification failed (Ed25519).');
  }
}