Date: Wed, 30 Oct 2013 14:07:28 +0100 From: Katja Malvoni <kmalvoni@...il.com> To: john-dev@...ts.openwall.com Subject: Re: ZedBoard: bcrypt On Wed, Oct 30, 2013 at 10:17 AM, Solar Designer <solar@...nwall.com> wrote: > On Tue, Oct 29, 2013 at 07:48:35PM +0100, Katja Malvoni wrote: > > At the moment performance is 602 c/s, maximum frequency is 100 MHz. > > What has contributed to doubling the performance (since your previous > report)? I guess it could be performing the 4 S-box lookups all at > once, but then you're giving high numbers of cycles per round anyway: > That is correct, since most of the RAM is unused I'm storing each S-box twice. > I can't get one cycle delay block RAM to work. I also tried using RAM > > module from http://openwall.info/wiki/crypt-dev/files but on Zynq it has > > delay of 2 cycles. Same is with all the others variants I tried. > > Currently one BF round takes 3 cycles - two for reading data from S-box > > (I'm using two block RAMs so all 4 values are fetched in those 2 cycles) > > and one to compute L and R when data is available. > > I'm not sure I understand how you're counting cycles here. Let's look > at one Blowfish round on its own. Are you doing this? - > > Cycle 0: initiate 4 S-box lookups > Cycle 1: wait > Cycle 2: compute new R; swap L and R > > Cycle 3: ready to start next round (initiate 4 S-box lookups, etc.) > Yes, I am. > If so, does anything prevent you from optimizing this to? - > > Cycle 0: compute new R; swap L and R; initiate 4 S-box lookups > Cycle 1: wait > > ... except possibly for the special cases of the first and the last > round? In the first round, bypass some of the logic. After the last > round, invoke the same logic, but bypass the S-box lookups. > As far as I can tell nothing prevents me to do that, I'm on it now. Katja Content of type "text/html" skipped
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