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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

#141

Post by LeoPanthera »

patcheudor wrote: post #55

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 mov…

Would attaching a heat sink to the top of the lamp solve that problem? So there's always a heat gradient.

It would probably work better in a colder room, too.

Re: A wall of lava lamps helps encrypt the internet

#142

Post by Bromskloss »

schoen wrote: post #130

A lot of confusion in this discussion thread and other promotions of this idea stems from the intuition that you can "run out" of entropy in your random number pool if you don't periodically replenish it with a physically unpredictable source. I have had this intuition too. Two things that feed it are the Linux random(4) man page and the behavior of GPG when generating a new private key. tptacek tried to explain some…

I've read that post now and previously (though not its references) and I feel that it never gets to the point where it explains how urandom can be equally safe as random.

Is the idea not that it is information-theoretically safe, but rather that the computational requirements are too great to figure out the state of the random-number generator even after a large amount of observed output?

Re: A wall of lava lamps helps encrypt the internet

#143

Post by Bromskloss »

patcheudor wrote: post #55

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 mov…

Would a heat sink on top help, perhaps?

Re: A wall of lava lamps helps encrypt the internet

#144

Post by s0rce »

LeoPanthera wrote: post #141
patcheudor wrote: post #55

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 mov…

Would attaching a heat sink to the top of the lamp solve that problem? So there's always a heat gradient. It would probably work better in a colder room, too.

Put a TEC on the top with a heatsink if your room is warm.

Re: A wall of lava lamps helps encrypt the internet

#145

Post by mygo »

_wp3r wrote: post #132
gerdesj wrote: post #110

Earlier quoted context omitted.

Not only that but your cameras are going to have to be precisely in the same place as theirs, with an identical view and be identical models with identical sensor variation, dust on lens etc etc etc ad nauseam. As you say, that might raise a few eyebrows.

Wouldn't you just cover their camera with paper or some other known pattern, if you were going to try that?

Great way to test how quickly you can get thrown out by security guards

Re: A wall of lava lamps helps encrypt the internet

#146

Post by schoen »

Bromskloss wrote: post #142
schoen wrote: post #130

A lot of confusion in this discussion thread and other promotions of this idea stems from the intuition that you can "run out" of entropy in your random number pool if you don't periodically replenish it with a physically unpredictable source. I have had this intuition too. Two things that feed it are the Linux random(4) man page and the behavior of GPG when generating a new private key. tptacek tried to explain some…

I've read that post now and previously (though not its references) and I feel that it never gets to the point where it explains how urandom can be equally safe as random. Is the idea not that it is information-theoretically safe, but rather that the computational requirements are too great to figure out the state of the random-number generator even after a large amount of observed output?

Yes, it's partly about comparing the security model of CSPRNGs to the security model of ciphers (and I think some of the CSPRNG constructions are extremely closely related to popular ciphers and hash functions). Part of the argument is that a cipher can encrypt an extremely large amount of data under the same key, and in the same way a CSPRNG can create an extremely large amount of pseudorandom output from a small seed. In some cases, deriving the internal state of the CSPRNG from observed outputs should be as difficult as deriving the secret key of a cipher from observed ciphertext or from known plaintext/ciphertext pairs. Maybe tptacek can do another go-round on this topic and make this more explicit (because he certainly still gets frustrated about people's intuitions when it comes up).

There was something either in that piece or in another one by another crypto expert saying that if we don't believe that CSPRNGs have this security property, we shouldn't believe in the symmetric ciphers that we use them to generate key material for either, because they are constructed using the same kinds of techniques.

I also don't remember what Matthew Green disagreed with Thomas about here.

Re: A wall of lava lamps helps encrypt the internet

#147

Post by bjoli »

Kequc wrote: post #80

That's approximately 100 lava lamps each at 100W = 10,000W = 10kW/h * 20.4 cents = $2.04/h * 24 = $48.96/day $1,489.20/month. Ignoring the fact that is very little money in Silicon Valley. Lava lamps consume a large amount of electricity in order to generate the heat they need. There are cheaper better ways to generate randomness, this is purely for spectacle clearly. It makes me nervous more than anything. If that's…

If you want to go with lamps or light as the source of entropy and still have a nice wall to show people, plasma globes are probably a better way of doing it.

Re: A wall of lava lamps helps encrypt the internet

#148

Post by JdeBP »

Bromskloss wrote: post #142
schoen wrote: post #130

A lot of confusion in this discussion thread and other promotions of this idea stems from the intuition that you can "run out" of entropy in your random number pool if you don't periodically replenish it with a physically unpredictable source. I have had this intuition too. Two things that feed it are the Linux random(4) man page and the behavior of GPG when generating a new private key. tptacek tried to explain some…

I've read that post now and previously (though not its references) and I feel that it never gets to the point where it explains how urandom can be equally safe as random. Is the idea not that it is information-theoretically safe, but rather that the computational requirements are too great to figure out the state of the random-number generator even after a large amount of observed output?

Then you might find that Thomas Hühn's approach helps you.

* https://www.2uo.de/myths-about-urandom/

The "another crypto expert" mentioned by schoen is Daniel J. Bernstein, quoted directly by Hühn.

Re: A wall of lava lamps helps encrypt the internet

#149

Post by JdeBP »

hinkley wrote: post #122
adzm wrote: post #96

Earlier quoted context omitted.

40W on mine fwiw

As someone else pointed out, they overheat. So if you want to run them all day you might go down to a 30 or 25 watts. But there are probably a bunch of other Brownian motion machines you could use that take a lot less power. Like those glitter lamps. You’d need a higher res camera.

Infinite improbability is just around the corner, eh? (-:

Re: A wall of lava lamps helps encrypt the internet

#150

Post by ScottBurson »

Houshalter wrote: post #18
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?

What would be an easier way? A wall of lava lamps seems pretty easy to set up.

If you want the same kind of visual display but with much lower power consumption, a much higher bit rate, and better reliability, I'd suggest a few plasma spheres, e.g.: https://www.scientificsonline.com/product/nebula-plasma-ball
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