decrypt method
Decrypts data using RSA.
Implementation
@override
List<int> decrypt(List<int> data) {
if (_privKey == null) {
throw StateError('Private key is required for decryption');
}
final decryptor = OAEPEncoding(RSAEngine())
..init(false, PrivateKeyParameter<RSAPrivateKey>(_privKey!));
return decryptor.process(Uint8List.fromList(data));
}