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Message-ID: <20170203155025.GA18612@openwall.com>
Date: Fri, 3 Feb 2017 16:50:25 +0100
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: to Single or not to Single

Jim,

On Fri, Feb 03, 2017 at 04:34:57PM +0100, Solar Designer wrote:
> ./configure --disable-native-tests CFLAGS='-O2 -mno-sse2 -mno-mmx -U__SSE__'
> make -sj8
> 
> to produce a non-SIMD build, so that you'd have a lower min_keys_per_crypt.
> 
> Combined, these settings will save you some memory on allowing for much
> smaller per-salt buffers of candidate passwords.  (Normally, "single
> crack" mode buffers from 128 to 1024 candidate passwords per salt, to
> benefit from bitslicing, SIMD, OpenMP, etc. and to amortize the overhead
> of salt switching.)
> 
> $ time ./john --single=None --nolog --verbosity=1 pw-1M
> Using default input encoding: UTF-8
> Loaded 1000000 password hashes with 1000000 different salts (dynamic_25 [sha1($s.$p) 64/64])

BTW, the 64/64 reporting here is probably a bug.  Without SIMD, SHA-1
can reasonably use at most 32 bits.  So it should be 32/64 here, no?

Alexander

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