6 ms·
Cloudflare uses lava lamps as a random number generator
- jmcguckin 9y agoNothing new here, move along. This was first done by SGI ages ago... joe
- joezydeco 9y agoArticle+Cloudflare acknowledges this (although they credit Sun not SGI)
- Chaebixi 9y agoSo they created a giant side-channel by putting their entropy-source next to a public window?
- CodeWriter23 9y agoPretty sure an attacker would have to observe the array from the same point of perspective as the camera to mount a successful side channel attack.
- serf 9y agodon't forget the room heating. I'm sure a wall of of 25-100w incandescents can get pretty toasty. very green.
- CorvusCrypto 9y agoI'm guessing they use this alongside CSPRNGs. Would make sense given the theorem that states any random number XORed with even highly-ordered input maintains its entropy.
- londons_explore 9y agoThere are lots of people in the crypto world who have serious issues with XORing random sources together. I haven't yet seen a good argument why it's a bad idea, and part of me thinks it might be a way to get more software using "rdrand" or other insecure sources unmodified.
- CorvusCrypto 9y agoI think the bad idea stigma stems from people XORing from the same source. That totally is a bad idea, but if two sources are wholly independent, the maximum entropy in the combined systems is maintained. To the people that just say it's never a good idea and scoff at any reasoning I'd remind them about OTPs. They are a special case related to this principle of XORing two independent sources together where only one input is random and it is proven mathematically to work.
- wellboy 9y agoIs this a perfect rng at the current state of technology? If not, why and are there currently perfect ones. What would an rng require to be perfect?
- antonvs 9y agoI'm now looking forward to a future article from security researchers: "Prediction of a random stream from a lava lamp model constructed from entropic data inferred from encrypted packets"
- ScottBurson 9y agoI would use plasma spheres (e.g. [0], but there are lots of them out there). A single plasma sphere generates a visual display that changes much faster and is much less predictable moment-to-moment than a lava lamp -- so you wouldn't need nearly so many of them -- and uses much less power into the bargain. [0] https://www.scientificsonline.com/product/nebula-plasma-ball https://www.scientificsonline.com/product/nebula-plasma-ball