anchor.diff:    // TODO: add unwrapKey support
   
     Future<List<int>> exportRawKey();
  +
  +  Future<Map<String, Object>> exportJsonWebKey();
   }
   
   abstract class AesCbcSecretKey implements CryptoKey {
  
positive.code:     @required List<KeyUsage> usages,
    }) {
      ArgumentError.checkNotNull(keyData, 'keyData');
      ArgumentError.checkNotNull(extractable, 'extractable');
      checkAllowedUsages('RSA-OAEP', usages, [
        KeyUsage.decrypt,
  
negative.code:     @required HashAlgorithm hash,
    });
  
    Future<List<int>> exportRawKey();
  
    Future<List<int>> exportSpkiKey();
  
    Future<Map<String, Object>> exportJsonWebKey();
  }
  
  abstract class RsaOaepPrivateKey implements CryptoKey {
  