Message-ID: <CAOLP8p5OoUqzdY549uyXHneRfa3tOkkJ+LGaLXyeGzALferh9g@mail.gmail.com>
Date: Thu, 3 Apr 2014 00:26:11 -0400
From: Bill Cox <waywardgeek@...il.com>
To: discussions@...sword-hashing.net
Subject: Tortuga issues

I wonder if it would make sense to combine threads about different
hashing schemes somehow...

Tortuga fails on both windows and Linux for > 1MiB m_cost, due to
allocating hashing memory on the stack.  The algorithm relies on a
sponge construction called "Turtle".  I'm not sure if this is a
documented sponge construction or a new one, but the mixing looked
iffy to me (is that scientific enough?), so I generated random data
with it bash it using:

for i in `seq 400000`; do ./test 256 1 1 $i s; done > foo

I added a print statement to test.c to print every 4 bytes of output
as an unsigned int.  This generated over 23MiB before I killed it,
which I fed into the dieharder tests.  It failed the first test, the
birthday test.

What this means is that with t_cost == 1, and m_cost == 1, the output
hash for different passwords is not very random at all.  It's possible
the error is in my code to print the data, but I think I got it right.
 I would recommend that the author generate output hashes for many
input passwords and verify that they pass some statistical tests for
randomness, such as the dieharder tests.  There may be some simple bug
in his code causing this result.

I think I'm going to have to do this test on all 24.  Is someone
working to create a standard test for each PHS function?  It would be
simple to call that for each entry and test the resulting hashes for
basic randomness.

Bill

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