4 ms·
This is why CloudFlare has done what they did with the lava lamp wall. Not that the wall is such a great source of entropy on its own - I'm sure it's not their
by LocalH 5mo ago
This is why CloudFlare has done what they did with the lava lamp wall. Not that the wall is such a great source of entropy on its own - I'm sure it's not their only source, but you can never have too many sources of entropy - but it makes it visible in a way that can grab those who don't fully understand the concepts of RNGs and how entropy plays into that.
The more sources of entropy, the more closely you approach "perfect" randomization. And a large chunk of those entropy sources need to be non-deterministic. Even on the small level, local applications running on local systems, like games, can use things like the mouse coordinates, the timings between button presses, the exact frame count since game start before the player presses Start to greatly enhance randomness while still using PRNGs under the hood
Yes, for the latter, that's technically deterministic (and the older the game considered, the more deterministic it is, see TAS runs of old games obliterating the "RNG"). But when you have fifty different parameters feeding into the initial seed, that's fifty things an attack would have to perfectly predict or replay (and there are other ways to avoid replay attacks that can be layered on top)
If CloudFlare had less than 100 different sources of entropy, I'd be disappointed. And that's assuming their algorithm for blending those entropy sources into a single seed value is good
- victorbjorklund 5mo agoIf I understand it the Lava lamps are 90% PR/fun. They have a lot of other sources for entropy that scales better.
- euroderf 5mo agoAnt farm ? Hamster wheels ? Anything critter-driven should provide some entropy.
- BSVogler 5mo agoI once read that noise of camera in total darkness is apparently a good source.
- unilynx 5mo agoThe noise probably makes the lava lamp wall just as effective as pointing the camera at the Mona Lisa - the lamps themselves are not that unpredictable frame-to-frame.
- LocalH 5mo agoFor the record, the lamps and camera are present in their lobby afaik, so you can actually go there, stand in front of them, and slightly affect the entropy. A cool parlor trick, certainly.
- amelius 5mo agoYou can already have a good entropy source from a single resistor. https://en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise https://en.wikipedia.org/wiki/Johnson%E2%80%93Nyquist_noise
- pyuser583 5mo agoThis is what gets me - entropy is hard, but not that hard. I get it goes against everything a computer is built to do, but so does telling time.
- wpm 5mo agoWould a CRT TV tuned to channel 3 and no RF input be a good source?
- ssl-3 5mo agoIn the sense that RF noise can be a source of entropy: Sorta*. But one doesn't need the whole thrift-store television set to do that; the visual aspect of a CRT displaying analog video snow just adds style points**. *: Sorta, because if someone discovers that the entropy is derived from an analog TV tuned to channel 3, then they also know how to influence it from outside. **: Style points can have value; it's OK to have fun with work. But that's a secondary function.
- 5mo ago
- FuriouslyAdrift 5mo agohttps://www.idquantique.com/random-number-generation/products/quantis-qrng-pcie/ https://www.idquantique.com/random-number-generation/product...
- conception 5mo agohttps://www.random.org/ https://www.random.org/ Uses atmospheric noise. These dudes use dice? https://youtube.com/shorts/ncoDq5EcPFg?si=lI6f9cw8dWcaDZ4Y https://youtube.com/shorts/ncoDq5EcPFg?si=lI6f9cw8dWcaDZ4Y
- throw-the-towel 5mo agoSpeaking of ants, Fourmilab (i.e. John Walker, of Autodesk fame) used to provide a random number generator powered by background radiation: https://www.fourmilab.ch/hotbits/ https://www.fourmilab.ch/hotbits/
- pverheggen 5mo agoYes, they also have wave machines, pendulums, and mobiles :) https://blog.cloudflare.com/harnessing-office-chaos/ https://blog.cloudflare.com/harnessing-office-chaos/ https://blog.cloudflare.com/chaos-in-cloudflare-lisbon-office-securing-the-internet-with-wave-motion/ https://blog.cloudflare.com/chaos-in-cloudflare-lisbon-offic...
- geon 5mo agoWouldn’t thermal noise in a resistor make more practical sense?
- drzaiusx11 5mo agoI prefer cosmic microwave background radiation (CMBR) as my RNG of choice
- iberator 5mo agountil someone uses microwave lol
- nyrikki 5mo agoThe original from SGI back in the mid 90's, before CPUs had RDRAND instructions etc... was a an actually practical solution. At the time I was at the Internet company that originally got online-gaming banned in the US, we were looking at CCDs and Cesium emitters that required a license etc... While I am not sure, it seems cloudflare basically implemented one after SGI's[0] patent expired. The patent and the licensing cost and adding SGI was a major blocker for us doing it, the startup closed before we found a real solution. But the best PRNGs like Blum Blum Shub were way too slow at the time. But things did improve quickly at that time. [0] https://patents.google.com/patent/US5732138A/en https://patents.google.com/patent/US5732138A/en
- pyuser583 5mo agoSGI was pretty amazing. I know some folks who worked there - Cray too. There’s a loyalty that just doesn’t exist any more - and arguably isn’t earned anymore.
- __s 5mo agoOld games are RTA viable to RNG manip: https://m.youtube.com/watch?v=Bgh30BiWG58 https://m.youtube.com/watch?v=Bgh30BiWG58
- dheera 5mo agoThe lava lamps are just for show. You can get entropy just by plugging an oscilloscope into a pile of dirt and cranking the gain up.
- adrian_b 5mo agoAny high-gain amplifier can be used, with its input connected to a resistor or a diode. For instance you can use the microphone input of a PC, together with an additional external amplifier made with an audio amplifier integrated circuit or an operational amplifier integrated circuit and with a diode or a resistor at its input. The microphone input of PCs provides a 5 V voltage that can be sufficient as a power supply for a noise source plugged in it. Such a true RNG can be made on a small PCB with an audio jack, so you can plug it into any PC with microphone input and have a true RNG that you can trust better than the RNG included in modern Intel and AMD CPUs. In the past, many AMD CPUs had defective internal RNGs. Moreover, both for Intel and for AMD it is impossible to verify whether the internal RNG does what it claims to do or it generates predictable pseudo-random numbers.
- tliltocatl 5mo agoMeh. The problem is that it might start receiving you local radio station and end up deterministic enough to screw you. So you need to shield the dirt properly.
- deleted 5mo ago[deleted]
- greiskul 5mo ago> you can never have too many sources of entropy This is so true. And the beauty is that with algorithms, we don't even need to know much about the entropy to be able to extract it. There is the Von Neumann method of generating an unbiased coin from a biased coin. Of throwing it twice, and checking if you got HT or TH. And completely discarding all HH or TT results. It doesn't matter if the coin you are using is 20% or 80%, the result will be a true 50/50. There are more modern algorithms that can be even better (in that they need less coin tosses if you have a very unbalanced coin). And then there is modern cryptographic hashing. Feed it all the bits you can. Collisions end up only happening in the real world if every single one of those bits is identical. So if you have actual entropy being fed, that cannot be controlled, predicted, or replicated, modern cryptography tells you that the end result is unique.
- ms_menardi 5mo ago> There is the Von Neumann method of generating an unbiased coin from a biased coin. Of throwing it twice, and checking if you got HT or TH. And completely discarding all HH or TT results. It doesn't matter if the coin you are using is 20% or 80%, the result will be a true 50/50. This blew my mind. Thank you! I had to think about it a bit, so for anyone scratching their head right now trying to figure it out, consider it this way: what matters is the ordering, of heads-then-tails, or tails-then-heads. It doesn't matter that it's biased one way or the other, if you keep flipping pairs until you get a result with two different values, it's a 50/50 chance whether the less-likely result comes first, or second. You might only have a 20% chance of any particular pair having a tails (for example), but in the cases where you do have a tails, it's a 50/50 chance that it comes first or second.
- throwaway89865 5mo agoNot very random if it's only TH or HT. Trivial to brute force with no more than two tries!
- susam 5mo agoAnd for people who like equations, here is my attempt at explaining it. Assume each flip is independent and the bias remains same in each flip. Let P(H) = p, P(T) = 1 - p. Then P(HH) = p^2, P(HT) = p(1 - p), P(TH) = (1 - p)p, P(TT) = (1 - p)^2. Therefore P(HT or TH) = 2p(1 - p). Now calculate P(HT | HT or TH) = p(1 - p) / (2p(1 - p)) = 1/2, P(TH | HT or TH) = (1 - p)p / (2p(1 - p)) = 1/2.
- bmitc 5mo ago> This is why CloudFlare has done what they did with the lava lamp wall. Interesting. I wonder how true it actually is that they use it like they claim here: https://www.cloudflare.com/learning/ssl/lava-lamp-encryption/ https://www.cloudflare.com/learning/ssl/lava-lamp-encryption.... It's in one of their lobbies, so doesn't that make it susceptible to an attack in some way? I'm not knowledgeable enough to know, but I figured if they actually used that method, they'd have a more controlled environment. I also don't fully understand it. A large part of that wall is static. And the camera isn't going to pick up on the stochastic properties of the lava as much as exists in the real world. So it feels like their images will be very statistically similar.
- Melatonic 5mo agoIt's probably just one of many sources. Just by being in one physical location it would be vulnerable to a network outage (ignoring any potential for attacks)