Re: [9fans] crypto question

[Karl Magdsick <kmagnum@gmail.com>]

 > Doesn't p9sk1 still use DES? DES was nice, but has several
> recognized ways to speed up cryptanalysis of the algorithm. 3DES
> is an alternative, but with combinations such as Rijndael-256 in
> CBC mode (or indeed, using a strong stream cipher -- Helix looks
> neat, but it's still too new, I think), I really don't see why
> we should stick with these things.

FYI, sufficiently useful quadratic approximations (XSL attack) of AES
exist to reduce all key lengths of AES to equivalent of no more than
128-bit strength.  These attacks will likely be improved in the
future.  The same class of attacks reduces Serpent to no more than
equivalent 192-bit key strength.  The key-dependent substitution
tables used in TwoFish appear to make it immune to this sort of
attack.  If you're going to pick an AES finalist block cipher, TwoFish
now appears to be the strongest of the AES finalists (especially the
legally unencumbered ciphers), despite Rijndael being chosen for AES.


-Karl