
Cloudflare uses lava lamps as a random number generator - dethi
https://www.fastcodesign.com/90137157/the-hardest-working-office-design-in-america-encrypts-your-data-with-lava-lamps
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antonvs
I'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"

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Chaebixi
So they created a giant side-channel by putting their entropy-source next to a
public window?

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CorvusCrypto
I'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.

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londons_explore
There 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.

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CorvusCrypto
I 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.

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ScottBurson
I 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)

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wellboy
Is 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?

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jmcguckin
Nothing new here, move along.

This was first done by SGI ages ago...

joe

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joezydeco
Article+Cloudflare acknowledges this (although they credit Sun not SGI)

