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Message-ID: <01b201cf187d$90275870$b0760950$@acm.org>
Date: Thu, 23 Jan 2014 12:56:17 -0800
From: "Dennis E. Hamilton" <dennis.hamilton@....org>
To: <discussions@...sword-hashing.net>
Cc: <waywardgeek@...il.com>
Subject: RE: [PHC] Initial multiply-compute-hardened Catena-3 benchmark
I notice that "timing attack" is used here yet I don't think the usual use of that term seems to apply.
Do you really mean that there is a feasible way to mitigate a work factor that a particular measure imposes?
Maybe those should be "speed-up" or "accelerator" attacks?
If you do mean "timing attack," please say more about what you are thinking of.
- Dennis
-----Original Message-----
From: Bill Cox [mailto:waywardgeek@...il.com]
Sent: Thursday, January 23, 2014 11:10
To: discussions@...sword-hashing.net
Subject: [PHC] Initial multiply-compute-hardened Catena-3 benchmark
I've signed in a branch of Catena that replaces the hashing function
with a simple multiply, OR, and ADD. I also made it hash blocks of
4096 bytes of memory at once rather than 64. The result runs 13X
faster, filling 1GB of memory in 1.37 seconds on a single thread.
In comparison, NoelKDF hashes 1GB in 0.42 seconds on 1 thread, or 3.2X
faster. However, there's a TMTO attack against NoelKDF that requires
almost the same runtime, but only uses 0.5GB. There is no such attack
against Catena-3, IMO.
Taking that into account, Catena-3 takes only about 40% longer to hash
the same memory as an attacker optimized version of NoelKDF. I'm
leaning towards Catena-3 now, for timing attack resistance, at least
if we have an option for a fast hash in the inner loop.
Bill
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