phc-discussions - Geeks like us can't write...

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Message-ID: <CAOLP8p5etdizWyW-VtQtxAWgJoui4On+dC9H_8k2H64WpwGU-w@mail.gmail.com>
Date: Sat, 12 Apr 2014 00:28:33 -0400
From: Bill Cox <waywardgeek@...il.com>
To: discussions@...sword-hashing.net
Subject: Geeks like us can't write...

My favorite author in this competition is Solar Designer.  I just love
his code.  It's that simple.  I'm also a big fan of  Samuel Neves
code, but he didn't submit an entry, though many of us are using his
Blake2 implementation.  I read all the authors' papers.  The best
paper, IMO, may be Catena.

Here's the sad part.  In the PHC, to varying degrees, good code is
anti-correlated with good writing.  I may not be able to write a good
paper, but I can tell when I'm reading one.  I can also tell when I'm
reading inspired code.

My wife is a writer.  She married me anyway :-)  I hear her complain
all the time that her interns or other writers "buried the lead",
which is when we don't put the most interesting stuff at the top to
help those of us who are too lazy to read papers carefully.

Solar Designer, as well as several of the more amazing coders, buried
the lead.  I want to fill in the "Strengths" section of the wiki for
Yescrypt, and I thought just taking a quick peek at his paper would
help me with the bullet points.  Nope!  The Catena paper made whole
chapter headings out of bullet-point strengths, but Yescrypt buries
the goodness in the details.

Anyway, without a list of bullet points for Yescrypt to copy (like I
did for Catena) I'm having to do what I suck at: write them myself!

So, what are the most impressive strengths of Yescript, since Solar
Designer didn't list them at the top of his paper?  I'm thinking:

- Most full featured and flexible entry in the PHC
- Script upwards compatible
- Highly tuned, and very fast
- Suitable for a variety of applications and platforms

Broad array of tunable defenses (needs it's own list):
- High external RAM usage, high DRAM bandwidth, high cache bandwidth,
any one of which can limit an attacker
- Tested and proven Bcrypt-like GPU defense, even while busting out of
cache into main memory
- Compute time hardened with serial multiplication chains
- Optimised a wide range of CPUs from older AMD to the latest Intel Haswell
- ROM optimized for improved authentication server performance and defense

The nuance in his work is what blows me away.  I had to work my butt
off for three months hacking TwoCats just to keep up with the good
ideas he hammered out like a machine.  How do you describe in bullet
points that the code was written by a freaking genius, optimized at a
level of detail that will blow most people's minds?

So, I'm afraid my effort at listing "Strengths" bullets is going to
fall short.  Several outstanding coders in this competition have a
similar problem.

Bill