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A wall of lava lamps helps encrypt the internet

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Re: A wall of lava lamps helps encrypt the internet

#51

Post by Sir_Cmpwn »

rm999 wrote: post #23
samuel wrote: post #17

I might be prejudiced, but this looks like a big PR stunt/done for the cool factor kind of thing. Aren't there simpler/saner alternatives for getting good randomness?

For sure. In another office they use a geiger counter (a much more standard way to get randomness, and probably easier to setup). That said, this doubles as a public art installation in their lobby - something many companies spend thousands (or millions!) of dollars on. So it's not just PR, it's actually surprisingly practical.

I know I'm nitpicking here - it's a private art installation.

Re: A wall of lava lamps helps encrypt the internet

#52

Post by pvg »

blattimwind wrote: post #48
pvg wrote: post #31

Earlier quoted context omitted.

The zillions of sources of EM/thermal/etc noise. It's so prevalent, most of the time the effort is spent in trying to get rid of it.

Very wideband Zener noise sources are a common piece of measurement equipment; and many folks built their own noise sources (also for RNGs) using Zener junction breakdown. While building my own I needed quite a bit of shielding to avoid interference issues by RF sources (mostly HF fluoerescent lights and LEDs), so these sources might be susceptible to bias by EMI...? Other junction breakdowns have noise as well, resi…

Such sources are always post-processed to deal with bias and correlation. No sane implementation just takes the straight measured output, whether it's keyboard interrupt timing or radioactive decay.

Re: A wall of lava lamps helps encrypt the internet

#53

Post by jstanley »

rm999 wrote: post #23
samuel wrote: post #17

I might be prejudiced, but this looks like a big PR stunt/done for the cool factor kind of thing. Aren't there simpler/saner alternatives for getting good randomness?

For sure. In another office they use a geiger counter (a much more standard way to get randomness, and probably easier to setup). That said, this doubles as a public art installation in their lobby - something many companies spend thousands (or millions!) of dollars on. So it's not just PR, it's actually surprisingly practical.

If it was a public art installation, wouldn't that leak their entropy?

Re: A wall of lava lamps helps encrypt the internet

#55

Post by patcheudor »

My lesson from my personal experiments with Lavarand: you must have more than one lamp, not necessarily for more entropy, but for fail-over and uptime. At approximately ~30 hours, my vintage 70's lamp 'gives up' - the fluid temperature becomes pretty even between the bottom and the top. It's all essentially superheated as far as the wax is concerned and it simply stays in one place as a dome at the bottom, barely moving. This isn't good for creating random data. By using multiple lamps, it's possible to power cycle them. Ideally, every ten hours or so, remaining off for a couple hours.

Re: A wall of lava lamps helps encrypt the internet

#56

Post by Quenty »

comboy wrote: post #44
MBCook wrote: post #24

Earlier quoted context omitted.

That would be susceptible to traffic patterns.

Cars don't look exactly the same and are not in the exact same places. Lighting changes. People look very different and walk different paths. It's going through PRNG so even very small pixel differences (which you can find even on an empty street thanks to changing weather, litter, wind and so on) are good enough if they are unpredictable. In other words, when you compare pictures of the same lava lamp with pictures…

My guess is there’s still enough noise it doesn’t matter.

Re: A wall of lava lamps helps encrypt the internet

#57

Post by adam_w_02125 »

noir_lord wrote: post #50
gruez wrote: post #46

Earlier quoted context omitted.

>As the material decays, its rate of generating bits of data slows down. can't you use something with a really long half-life?

but then your initial rate is much slower.

So get more material!
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