[108106] in Cypherpunks
lavarand
daemon@ATHENA.MIT.EDU (Anonymous)
Thu Feb 4 18:13:57 1999
Date: Thu, 4 Feb 1999 23:50:49 +0100
From: Anonymous <nobody@replay.com>
To: cypherpunks@toad.com
Reply-To: Anonymous <nobody@replay.com>
Besides having a very cool, dry wit, the lavarand folks understand
the distillation of entropy. Don't skip the rest of the site,
its worth reading, but here's some well-referenced meat.
http://lavarand.sgi.com/cgi-bin/how.cgi
Step 3: Cryptographically hash the digitization of the chaotic system
(Feed the digital output through a number munger):
The digital output of the image is then munged by an algorithm, which
compresses and scrambles it. Thus the 921,600-byte image is transmogrified
into an 140-byte "seed."
The technogeek explanation :
We use NIST's Secure Hash Standard rev 1 (SHS-1, sometimes called the
Secure Hash Algorithm or SHA-1) to cryptographically hash the digitized
image of the chaotic system (Lava Lite lamps) produced in step 2.
Our implementation of SHS-1 allows for the production of an n-way hash. An
n-way hash produces n hash values, each of which is a hash of a every nth
octet. In this example we use a 7-way hash, each of which produces a 160
bit value from every 7th byte of the digitized image. By hashing every 7th
byte we avoid hashing the same byte of each pixel.
