When calling `AES.decrypt_into()` or `AES.encrypt_into()`, the
destination buffers may be any buffer kind. However, we currently
aren't checking to make sure the destination buffer is actually
writable.
Specify `MP_BUFFER_WRITE` for the destination buffers of both of these
objects so we don't inadvertently write to immutable data.
Signed-off-by: Sean Cross <sean@xobs.io>
In order to accept both `bytes` objects and `bytearray` objects, use a
`bufinfo` construct to retrieve the data rather than
`mp_obj_str_get_data()`.
Signed-off-by: Sean Cross <sean@xobs.io>
This adds initial support for an AES module named aesio. This
implementation supports only a subset of AES modes, namely
ECB, CBC, and CTR modes.
Example usage:
```
>>> import aesio
>>>
>>> key = b'Sixteen byte key'
>>> cipher = aesio.AES(key, aesio.MODE_ECB)
>>> output = bytearray(16)
>>> cipher.encrypt_into(b'Circuit Python!!', output)
>>> output
bytearray(b'E\x14\x85\x18\x9a\x9c\r\x95>\xa7kV\xa2`\x8b\n')
>>>
```
This key is 16-bytes, so it uses AES128. If your key is 24- or 32-
bytes long, it will switch to AES192 or AES256 respectively.
This has been tested with many of the official NIST test vectors,
such as those used in `pycryptodome` at
39626a5b01/lib/Crypto/SelfTest/Cipher/test_vectors/AES
CTR has not been tested as NIST does not provide test vectors for it.
Signed-off-by: Sean Cross <sean@xobs.io>
