Using a CRC to authenticate a message is why we have an SSHv2; SSH made a similar mistake.
Thanks Thomas, I updated the post.
Strange that python-crypto would take care of padding for block ciphers and not calculate the CRC for you. I wonder how much code out there assumes it would and become susceptible to accidental corruption of the plaintext.
"Accidental". Heh.
Great Tutorial! An excellent way to get into Python Crypto Lib.