AES GCM without MAC fails after 2.0 upgrade about cryptography HOT 4 CLOSED

In 1.0 and many other implementations of AES-GCM, the MAC is concatenated to the end of the cipher text. This is what I do:

import 'package:cryptography/cryptography.dart';

final sha256 = Sha256();

/// Returns a [SecretBox] that is compatible with our past use of AES-GCM where the cipher text
/// was appended with the MAC and the nonce was stored separately.
SecretBox secretBoxFromDataWithMacConcatenation(
  Uint8List data, {
  int macByteLength = 16,
  Uint8List nonce,
}) =>
    SecretBox(
      Uint8List.sublistView(data, 0, data.lengthInBytes - macByteLength),
      mac: Mac(Uint8List.sublistView(data, data.lengthInBytes - macByteLength)),
      nonce: nonce,
    );

It would be nice if this were integrated into the package though or even the default as it is a rather common pattern.

from cryptography.

@CDDelta Aha! This worked! Thank you so much. Adding this to the docs would be extremely helpful! Another typo in the docs is that decrypt calls encrypt instead of decrypt

from cryptography.

Without this fix, the new API breaks compatibility with encrypted data created with prior versions of this library. That seems like a big issue to me, possibly leading to errors when the workaround is applied incorrectly, and definitely making it harder to use this package. Are there no plans to address this highly severe issue?

from cryptography.

Why is this issue closed? The documentation is still not fixed, and the issue still exists.

from cryptography.