sign method

  1. @override
Future<Signature> sign(
  1. List<int> message, {
  2. required KeyPair keyPair,
})

Signs bytes.

Example

In this example, we use Ed25519:

import 'package:cryptography/cryptography.dart';

Future<void> main() async {
  final signedMessage = [1,2,3];

  final ed25519 = Ed25519();
  final keyPair = await ed25519.newKeyPair();
  final signature = await ed25519.sign(
    signedMessage,
    keyPair: keyPair,
  );

  // ...

  final isRealSignature = await ed25519.verify(
    signedMessage,
    signature: signature,
  );

  print('Signature verification result: $isRealSignature');
}

Implementation

@override
Future<Signature> sign(
  List<int> message, {
  required KeyPair keyPair,
}) async {
  if (isSupportedPlatform) {
    final keyPairData = await keyPair.extract();
    if (keyPairData is! RsaKeyPairData) {
      throw ArgumentError.value(
        keyPair,
        'keyPair',
      );
    }
    final result = await invokeMethod(
      'RsaPss.sign',
      {
        'data': base64Encode(message),
        'd': base64Encode(keyPairData.d),
        'e': base64Encode(keyPairData.e),
        'n': base64Encode(keyPairData.n),
        'p': base64Encode(keyPairData.p),
        'q': base64Encode(keyPairData.q),
      },
    );
    final bytes = base64Decode(result['bytes'] as String);
    return Signature(
      bytes,
      publicKey: await keyPairData.extractPublicKey(),
    );
  }
  return await fallback.sign(
    message,
    keyPair: keyPair,
  );
}