[PYTHON-CRYPTO] aes library

[Paul Rubin]

    Pardon my ignorance as I am rather new to this list, and even
    though my interest in cryptology is quite large, I don't really
    have a grip on AES in the way the way that I would want to
    have(One of the major reasons for me joining this list). Recent
    mails have included a whole bunch of abbreviations which I have
    absolutely no clue about, anyone feel like posting a link or a
    post explaining some of these to me? (CBC, CTR, etc...)  :=)

ECB, CBC, CFB and OFB are described here:

http://www.iks-jena.de/mitarb/lutz/security/cryptfaq/q82.html
http://www.iks-jena.de/mitarb/lutz/security/cryptfaq/q83.html

CTR is done by just encrypting the blocks 0001, 0002, 0003, ...
and xoring the resulting stream against the plaintext stream.

It has the advantage of being very simple, and not needing special
padding if you want to encrypt a plaintext of 23 bytes or something
like that.  Its disadvantages are that you must never re-use a key,
and it is somewhat more subject to ciphertext modification attacks
than other modes.  Flipping a single bit in the ciphertext results in
flipping the same bit in the plaintext without disturbing the
surrounding bits.