wader / aes-arraybuffer Goto Github PK

For english:
It corrupts files. The file size before encryption does not match after decryption in some situations.
Sample code: stand.tar.gz

Hi,

There is a subtle bug when you encode and pad the last block and that bock falls exactly on a 16 byte boundary). inside crypto.js library.

I've been passing files to various other platforms and things like opensll and they have an issue decoding any file when it exactly a multiple of 16 bytes.

this can be resolved by padding the file with 16 bytes (of 0x10) and then the decryption works on all platforms.

the code change required is

function pkcs_pad_buffer_to_append(length) {

  var pad_byte_count = pkcs_max_pad_byte_count - (length % pkcs_max_pad_byte_count);
  if (pad_byte_count===0) {
    pad_byte_count = 16;
  }

  var pad_u8 = new Uint8Array(pad_byte_count);
  for (var i = 0; i < pad_byte_count; i++) {
    pad_u8[i] = pad_byte_count;
  }

  return pad_u8.buffer;
}

Really appreciate your efforts on this library.
It has been worked very well and save lots of my time until I ran this on iPhone.

I don't think it's an issue from this library(maybe from iOS's problem), but wondering if there might be any work-around.

Issue: tests.html simply fail on iPhone, especially at test_aes_cbc_padding_symmetric()