Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Sat, 24 Mar 2012 12:03:28 +0100
From: Lukas Odzioba <lukas.odzioba@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Self test woes

2012/3/22 magnum <john.magnum@...hmail.com>:
> I do not have any particular proposition though. Any ideas? This format
> is extreme but I think the problem is noticable with most other GPU
> formats too.
Especialy for slow-ones this is a real problem.

> Just disabling self-test with a flag would be easy but
> that's not a good solution - we need the tests. Maybe we could have a
> flag that tells john to collate all tests into just one or two calls to
> crypt_all()?
This might introduce problems when tests won't be able to find some
"trash" values from previous crypt_all() runs.

We should think more about testing. I often had problems because
format working great on tests but not on a real crack. I tried to
solve it using unit testing last summer, it helped a bit, and thanks
for that I could propose some "trivial" tests that could be included
to jtr testing routine like simple comparision strcmp(arg1,arg2),
where set_key(k,arg1), and arg2=get_key(k). Problem might sound stupid
but I fall into if 2-3 times and others might too.

Maybe we could separate tests from benchmarks, what is now the problem
(formats needs a lot of hashes to get good performance).
All my formats now are using predefined or calculated once
keys_per_crypt value and do not care about crypt_all(int n) argument
at all.

Current solution has at least two disadvantages:
1) test takes too much time
2) we are spending gpu power on wordlist attacts, when size of
wordlist is much smaller than keys_per_crypt.

Lukas

Powered by blists - more mailing lists

Your e-mail address:

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.