Lavarand, also known as the Wall of Entropy
Lavarand

							

						From Wikipedia, the free encyclopedia
					A wall of lava lamps at the offices of Cloudflare

Lavarand, also known as the Wall of Entropy, was a hardware random number generator designed by Silicon Graphics that worked by taking pictures of the patterns made by the floating material in lava lamps, extracting random data from the pictures, and using the result to seed a pseudorandom number generator.[1]


Although the secondary part of the random number generation uses a pseudorandom number generator, the full process essentially qualifies as a "true" random number generator due to the random seed that is used.  However, its applicability is limited by its low bandwidth.
It was covered under the now-expired U.S. patent 5,732,138, titled "Method for seeding a pseudo-random number generator with a cryptographic hash of a digitization of a chaotic system." by Landon Curt Noll, Robert G. Mende, and Sanjeev Sisodiya.
From 1997 to 2001,[2]
there was a website at lavarand.sgi.com demonstrating the technique. Landon Curt Noll, one of the process's originators, went on to help develop LavaRnd, which does not use lava lamps.[3]  Despite the short life of lavarand.sgi.com, it is often cited as an example of an online random number source.[4][5]
As of 2017, Cloudflare maintains a similar system of lava lamps for securing Internet traffic.[6]



^ "Totally Random". Wired Magazine. Vol. 11, no. 8. August 2003.

^ "Welcome to Lavarand!". Archived from the original on 1997-12-10. Retrieved 2010-01-05.

^ "LavaRnd". Archived from the original on 2004-05-14.

^ U.S. patent 6,889,236

^ U.S. patent 7,031,991

^ Schwab, Katharine (2017-08-18). "The Hardest Working Office Design In America Encrypts Your Data–With Lava Lamps". Fast Company. Retrieved 2022-04-16.



Archived version of original Lavarand.com from Archive.org (pictures do not work)
Cloudflare Blog post - Randomness 101: LavaRand in Production
Cloudflare Blog post - LavaRand in Production: The Nitty-Gritty Technical Details




