passing IVs smaller than 16 bytes to pycryptopp.cipher.aes.AES uses uninitialized memory

[bj0]

test:

from pycryptopp.cipher import aes
import os

k = os.urandom(16)
N = 4
print repr(aes.AES(k, iv='\x00'*N).process('testing'))
print repr(aes.AES(k, iv='\x00'*N).process('testing'))
print repr(aes.AES(k, iv='\x00'*N).process('testing'))

The results from the first and second calls are different, making the encryption useless. It seems that if a full IV is not passed, uncleared/uninitialized memory is used, making the results unpredictable.

This constructor should throw an exception for IV lengths that don't match the block size (16).

Sort of related: ​http://tahoe-lafs.org/trac/pycryptopp/ticket/18

[warner]

Fixed by [c89e25aa/git]