RE: Password Cracking Challenge...

[Michael Wojcik <Michael.Wojcik () microfocus com>]

> From: David Riley [mailto:oscar () the-rileys net] 
> Sent: Monday, July 28, 2003 4:47 PM
>
> It is a good starting point, and that's what I thought of as well.
> However, the cutoff here seems to be 8 bytes instead of 7.  I'm still
> looking at it, but the encoding of the second chunk seems 
> dependent on the
> first (e.g. the "321" chunk of "Pa$$word321" is different than that of
> "Password321".

That, plus the fact that the first 8 bytes of the hashes for "Password123"
and "Password321" are the same, suggests to me a 64-bit block cipher running
in some chaining mode.  DES in CBC mode, for example.

The fact that all the hashes are 128 bits would suggest that the algorithm
either discards characters after the 16th, or perhaps that it uses the first
and last block of cipher output as the hash (which would be a little
better).  It'd be nice to have two sample vectors of 17-byte passwords, only
differing in the 17th byte, to check.

I'll leave further speculation to the actual cryptanalysts (assuming any of
them find this sufficiently interesting to bother).

-- 
Michael Wojcik
Principal Software Systems Developer, Micro Focus