Le 11/08/2011 21:36, Jim Henderson a écrit :
> On Thu, 11 Aug 2011 19:27:17 +0100, Orchid XP v8 wrote:
>> On the other hand, salting the password trivially defeats rainbow
>> tables.
> 
> Sure, but how many password systems don't use a salt value?

Are you aware that some current glibc2 version of crypt can move away
from the traditional one way function (DES) with a salt of 2 chars to
use an alternative hashing algorithm (MD5/blowfish/sha-256/sha-512) with
a salt in [a-zA-Z0-9./] of 16 chars (instead of 2).

There is also a pitfall: only SHA-* take into account the whole password
(MD5 stops at 8 chars, as does classical DES).

So, yes, "correct horse battery stapple" is a strong password on a
recent system which use sha.
But it is damn weak on an old system, where it get truncated to "correct
". (dictionnary attack, word +space, an easy rule)

The extended salt of MD5 is better against the rainbow book (DES rainbow
book are very short with only 2 chars of salt), but it is still
vulnerable to "correct " discovery.

-- 
Software is like dirt - it costs time and money to change it and move it
around.

Just because you can't see it, it doesn't weigh anything,
and you can't drill a hole in it and stick a rivet into it doesn't mean
it's free.

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