lavarand

[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.