Date: Mon, 1 Sep 2014 13:27:05 +0200
From: Dmitry Khovratovich <khovratovich@...il.com>
To: "discussions@...sword-hashing.net" <discussions@...sword-hashing.net>
Subject: Re: [PHC] A review per day - RIG

If you want to give a proper credit to the bit-reversal permutation in the
context of time-space tradeoffs, then it must be given first to Lengauer
and Tarjan (STOC'79, http://dl.acm.org/citation.cfm?doid=800135.804420 ),
who explored and proved the lower bound for the 1-layer case. The
bit-reversal permutation itself has been widely used even earlier, e.g. in
the context of FFT.

Best regards,
Dmitry


On Sat, Aug 30, 2014 at 12:01 AM, Bill Cox <waywardgeek@...hershed.org>
wrote:

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> As far as I can tell, RIG is a quick rewrite of Catena, using Lyra2's
> hash function, and Gambit's XOR-ing over data.  The combination is
> original, but that's all.  If the paper said, "We have combined these
> three good ideas and thing the result is superior", then I would be OK
> with it.  For example, someone needs to plug Lyra2's ultra-fast sponge
> into Gambit.  Mixing ideas is fine.  I just think it's weird pasting
> three ideas from the forum together without crediting the sources
> properly.  It almost seems like they attempted to obfuscate their
> sources.  The paper and code are all original (mostly), so there's no
> plagiarism here.  You can't copyright an idea.  However, it's
> offensive to use other's ideas and pretend they are your own.  All
> that is needed to fix RIG, IMO, is some proper credit to where they
> got their ideas, and a rewrite of their paper to be less dick-ish.
>
> For example, here's a statement in the RIG paper:
>
> "Therefore, it is recommended in [6] to have password-independent
> memory access patterns for a password hashing scheme. We have
> attempted to follow this requirement using bit reversal permutation."
>
> Why not credit Catena for the bit reversal pattern while they were at
> it?  Did they actually rip off Lyra2's hash function and not give them
> credit?  Multiple entries use the XOR-ing thing, so I have less
> trouble with that, but it follows a pattern...
>
> RIG's single-round Blake2b hash function happens to be identical to
> what Lyra2 uses.  They either both copied the exact same text from the
> exact same source, or RIG's hash function was actually copied from Lyra2.
>
> The XOR-ing over memory is an idea from Gambit that we talked about
> quite a bit.  Now that I've found that writing to a memory location
> just read from is quite fast compared to writing to a different
> location, I am a fan.
>
> Anyway, I feel RIG = Catena + Lyra2's hash + Gambit's XOR.  This is
> likely a good combination, but I have to feel for the Catena, Lyra2,
> and Gambit authors when their work is not credited properly.  I
> haven't done much analysis of the RIG code because it bothers me to
> read it... for example the memory swapping algorithm that the Catena
> guys invented fairly recently is there...
>
> Anyway, RIG is the last entry I'm posting about today!
>
> Bill
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-- 
Best regards,
Dmitry Khovratovich

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