Date: Wed, 6 Sep 2006 17:29:37 +0400 From: Solar Designer <solar@...nwall.com> To: john-users@...ts.openwall.com Subject: Re: fast MD5 for long passwords? On Mon, Sep 04, 2006 at 06:51:21PM +0100, Sam wrote: > I need a fast MD5 engine that will hash arbitrary length passwords. I > have looked at the MMX/SSE2 code in the latest John but I think it only > handles <=32 byte strings. Can anyone suggest how to modify this to > handle longer strings? (is that what the mdfivemmx_noinit_sizeupdate, > mdfivemmx_noinit_uniformsizeupdate and mdfivemmx_nosizeupdate functions > are for?) As Simon has pointed out, there's no MMX/SSE2-enhanced MD5 code in the latest JtR; the implementation you're referring to is a part of Simon's unofficial patches. As it relates to cracking "passwords" of more than 32 characters long, you're most likely out of luck - unless you have prior knowledge about the passwords (e.g., you know most of the characters and only need to recover a few forgotten ones). With "password" lengths like this, it also doesn't matter much whether your MD5 implementation is optimized or not. The use of SSE2 might make things, say, 2-4 times faster - whereas each additional unknown character increases the search time by at least the same factor. > Or does anyone know of a stand alone library that will do the same? OpenSSL includes a fairly optimal but non-parallelized generic MD5 implementation, or you can find one here: http://cvsweb.openwall.com/cgi/cvsweb.cgi/Owl/packages/popa3d/popa3d/md5/ P.S. For those who e-mail private stuff to me - I've got a new GnuPG key since the old one is due to expire soon. The new key is available off pgp.mit.edu. It's signed with the old key, as well as with the Openwall signatures key as available off the website. -- Alexander Peslyak <solar at openwall.com> GPG key ID: 5B341F15 fp: B3FB 63F4 D7A3 BCCC 6F6E FC55 A2FC 027C 5B34 1F15 http://www.openwall.com - bringing security into open computing environments Was I helpful? Please give your feedback here: http://rate.affero.net/solar -- To unsubscribe, e-mail john-users-unsubscribe@...ts.openwall.com and reply to the automated confirmation request that will be sent to you.
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