
Cloudflare Randomness Printer - jgrahamc
https://github.com/cloudflare/receipt-printer/
======
JshWright
Neat project!

You don't really need a lava lamp for this. The Raspberry Pi has a built-in
hardware RNG. As long as you have the right module loaded, a Pi is a pretty
good source of randomness.

~~~
Navarr
I think they're just using their internal entropy generator. They use the lava
lamps as part of that, and the internal generator for all sorts of stuff.

[https://twitter.com/grittygrease/status/727587915090403328](https://twitter.com/grittygrease/status/727587915090403328)

~~~
sucrose
Neat, I've never heard of the lava lamp wall before. That's extremely
interesting. For anyone else that is interested in how it works, I found this
explanation on Reddit from /u/kaihatsusha:

"Really good encryption relies on perfectly random / unpredictable numbers.

If you ask a computer to pick a random number, it can really only apply a
predictable but complicated calculation on some other number. It may appear
random to us but it isn't random to someone who can perform the same
calculation. It's like stacking the deck in Poker games.

In computers, "entropy" is essentially a measure of chaos; a bit of
information you can get from something that is truly unpredictable. So the
idea here is for a video camera to digitize a physical, chaotic phenomenon,
like lava lamps or fish in an aquarium or a busy city sidewalk. Use the
digitized photo as the core of the random-number generation proceas.

And then two computers could use the same secret random number to seed their
encryption; only those who know the secret number will be able to set their
Ovaltine Secret Decoder Ring to the correct setting (except in modern days
it's hundreds of rings with quintillions of positions each).

In the Cold War, we would do the same thing by measuring moisture in the
clouds or drawing numbered balls out of a lottery tumbler. Some crypto
programs ask the user to wiggle their mouse for a few seconds to generate
entropy. Make ONLY two copies of the data and those two people can communicate
secretly."

~~~
thwarted
The idea and implementation has been around a while. Lavarand was an early (or
first) one.

[https://en.wikipedia.org/wiki/Lavarand](https://en.wikipedia.org/wiki/Lavarand)

------
Scaevolus
Any photos of the end result? The gif ends too quickly!

~~~
JshWright
In a stunning lack of foresight, Cloudflare used the passwords on that
particular receipt as the root passwords for their production database
servers. They have to cut the gif short to avoid leaking them...

------
vs2
I don't get it? What's this for?

~~~
eastdakota
Fun.

~~~
vs2
oh ok! I like fun, just the right amount of fun tho

------
7ewis
That definitely is quite... random!

------
fapjacks
I hope the sudoku puzzle has a seizure trigger warning:
[https://www.theguardian.com/science/neurophilosophy/2015/oct...](https://www.theguardian.com/science/neurophilosophy/2015/oct/19/sudoku-
induced-epileptic-seizures)

