phc-discussions - Re: [PHC] A review per day

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 02 Sep 2014 13:51:14 -0400
From: Bill Cox <waywardgeek@...hershed.org>
To: discussions@...sword-hashing.net
Subject: Re: [PHC] A review per day - Schvrch

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 09/02/2014 11:23 AM, Samuel Neves wrote:
> You can alternatively represent stir's inner loop as follows:
> 
> const uint64_t x = state[(j+3)%256]; const uint64_t y =
> state[(j+2)%256]; const uint64_t c = (x^((x^y)|((x-y)^y))) >> 63; 
> carry ^= state[(j+1)%256] ^ (c - 1); state[j] ^= carry; carry +=
> mixer;
> 
> This way it might be easier to see how differences propagate from
> higher bits to lower bits.
> 

OK, I believe it now.  The LSB of carry is obfuscated by the parity of
number of comparisons that pass/fail.  Adding the mixer propagates
this upward.  Not that I'm really qualified to rate such things, but
it seems to me that it will mix properly given enough iterations.

This is why I'm sticking to reviewing the code :-)

Bill
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=GsLi
-----END PGP SIGNATURE-----