what's so special about lava lamps?
Nothing. They simple produce an ever changing picture which is impossible to predict.
Topic: Are dices for generating seed words fair? - page 3. (Read 3465 times)
I suggest everyone to watch this video made by Crypto Guide, it is very much related with this topic.
He explains how some unsecure hardware wallets (read Coldcard) are allowing owners to use weak dice method of generating seed phrases, that resulted in people losing coins.
Video is less than 10 minutes long:
https://www.youtube.com/watch?v=oj_W3xOlt6U
This doesn't mean we shouldn't use dices anymore, but we need to use them properly with high enough entropy.
He explains how some unsecure hardware wallets (read Coldcard) are allowing owners to use weak dice method of generating seed phrases, that resulted in people losing coins.
Video is less than 10 minutes long:
https://www.youtube.com/watch?v=oj_W3xOlt6U
This doesn't mean we shouldn't use dices anymore, but we need to use them properly with high enough entropy.
I'd suggest using few lava lamps instead for these reasons,
You don't even need to do any of that. As I discussed way back on page 2 of this thread, pointing your phone at a light source is enough to capture the shot noise, which is another truly random process and will produce truly random numbers. Here's a paper describing the process: https://arxiv.org/pdf/1405.0435.pdfwhat's so special about lava lamps?
Nothing. They simple produce an ever changing picture which is impossible to predict. I'd suggest using few lava lamps instead for these reasons,
1. You don't have to worry about spoiled banana.
2. Lava lamp is nice decoration for your guest room.
3. You can use your phone camera if you don't want to buy CCTV/security camera.
4. Big company such as CloudFlare already do that, https://blog.cloudflare.com/lavarand-in-production-the-nitty-gritty-technical-details/.
i thought maybe they were doing something more exciting with lava lamps like they had some electronic eye that counted how many blobs were in it every 20 seconds or something but no. nothing like that...
If we are collectively going to be this ridiculous about flipping a coin, then you might as well just get a Geiger counter and point it at the banana you have in your kitchen, given that radioactive decay is a truly random process.
I'd suggest using few lava lamps instead for these reasons,
1. You don't have to worry about spoiled banana.
2. Lava lamp is nice decoration for your guest room.
3. You can use your phone camera if you don't want to buy CCTV/security camera.
4. Big company such as CloudFlare already do that, https://blog.cloudflare.com/lavarand-in-production-the-nitty-gritty-technical-details/.
But on serious side, /dev/urandom is more than enough.
Or is there some structure behind it on the quantum level that we just don't understand yet?
We can never prove there isn't, because you obviously cannot prove a negative. I cannot prove that all radioactive decay is not actually caused by a sentient and ominpotent Russell's teapot choosing individual atoms to decay at an instant of its choice. What we do know is that there are no experiments or indeed even mainstream interpretations of quantum physics which say that radioactive decay is anything other than random chance (bound by the half life of the particular isotope in question).And if all of science can't predict the decay any better than random chance, then someone trying to hack in to your wallet couldn't either.
I do not know about you, but I believe anyone compromising these levels of randomness deserves the bitcoin.
given that radioactive decay is a truly random process.
Is it? Or is there some structure behind it on the quantum level that we just don't understand yet? And even if it's truely random, your measurements can still get compromised.Then again:
The generation of random numbers is too important to be left to chance.
But also:
Only God can make random selections.
If we are collectively going to be this ridiculous about flipping a coin, then you might as well just get a Geiger counter and point it at the banana you have in your kitchen, given that radioactive decay is a truly random process.
(But what about if the banana is really big or really small!? Or what if it has a slightly difference concentration of potassium-40 than average!? What if the laws of quantum physics are slightly different in my kitchen than in yours!?)
(But what about if the banana is really big or really small!? Or what if it has a slightly difference concentration of potassium-40 than average!? What if the laws of quantum physics are slightly different in my kitchen than in yours!?)
That was a very thorough analysis. But I do disagree that there might only be a 1 deg C temp difference.
I've seen you do this in more topics: you make a ridiculous claim, and stick to it despite overwhelming evidence of being wrong. Your first statement was there's a temperature difference between sides of the coin. I debunked that. Now you're saying the coin can get warmer. Nobody says a coin doesn't get warm if you hold it in your hand, but that's irrelevant for flipping the coin.yeah but do you agree the flipper of the coin must be blindfolded and toss the coin down a laundry chute into different room.
and a second person records the results
In the second room.
this eliminates the issue that the tosser can subconsciously influence and corrupt the von Neumann algorithm method.
This assumption was needed to calculate the required amount of heat transfering through the coin, and the result of the calculation made it clear it requires an unrealistic amount of heat.
now i realize the concern with your assumption that I have. you're assuming steady state i guess. who said anything about steady state? how fast does a penny achieve thermal equilibrium when it is sitting in the palm of someone's hand? you didn't even think about that and the model you plugged into only deals with "steady state".all you did is make an assumption that the temperature difference between the two sides was 1 deg C.
You're taking it out of context. This assumption was needed to calculate the required amount of heat transfering through the coin, and the result of the calculation made it clear it requires an unrealistic amount of heat.If you don't believe me or don't get it, I don't have time to try to convince you, sorry.
I've seen you do this in more topics: you make a ridiculous claim, and stick to it despite overwhelming evidence of being wrong. Your first statement was there's a temperature difference between sides of the coin. I debunked that. Now you're saying the coin can get warmer. Nobody says a coin doesn't get warm if you hold it in your hand, but that's irrelevant for flipping the coin.
you didn't debunk anything. all you did is make an assumption that the temperature difference between the two sides was 1 deg C. I said I thought it should be higher than that given that body temp is 98.6 and room temp is about 75. what's so ridiculous about that? at least I'm not assuming anything. like you.
maybe i don't understand the physics involved but if you have a laser thermometer maybe you can do this test and report back.
That was a very thorough analysis. But I do disagree that there might only be a 1 deg C temp difference.
I've seen you do this in more topics: you make a ridiculous claim, and stick to it despite overwhelming evidence of being wrong. Your first statement was there's a temperature difference between sides of the coin. I debunked that. Now you're saying the coin can get warmer. Nobody says a coin doesn't get warm if you hold it in your hand, but that's irrelevant for flipping the coin. 
But what about the fact that the heads and tails side have different engravings, meaning photons will hit them at a different angle, and that will produce a bias so imperceptibly small that it wouldn't even affect a single flip if you flipped a coin from now until the heat death of the universe? Better flip in a pitch black room just to be safe!
Ha, there is even more interesting scenario, that can be taken into account by paranoiacs.
Due to not zero entanglement of the distant electrons someone, let's say on the opposite side of universe, flipping his coins may influence your results here on Earth.
Just heat the room and every object in it including the coin to body temperature, and then there will be no net transfer to heat to or from any object. 
you would also need to do the coin flip in a vacuum since if there is air pressure then the side facing up will get exposed to a headwind which will tend to cool it off relative to the side that was exposed to the hand.Quote
These ever more ridiculous scenario are just that - ridiculous. Using von Neumann's algorithm and the same starting conditions for each flip is all that is needed to product a complete random string of bits.
you may be right but lets not pretend we are capable of ensuring the "same starting conditions" for each flip. that is impossible. due to heat, air pressure and things of that nature. and variations in the hardness of the surface being used, etc, etc. you assume they all even out. "even out". as though anyone really understands what that even means.Quote from: LoyceV
Okay, I'll bite. But in normal units. Let's assume there's a 1oC (or 1K) temperature difference between both sides of the penny.
That was a very thorough analysis. But I do disagree that there might only be a 1 deg C temp difference. Human body temp is 98.6 F and room temp could be 20 degrees less. I'm not saying we should assume the temp difference is 20 deg F but its probably more than just 1 deg C. Maybe 5 times that. 
Using von Neumann's algorithm and the same starting conditions
Let's add Heisenberg's uncertainty principle to the equation to make sure we can't ever know the exact starting conditions, and thus never reproduce it exactly. Now that I think about it: in this case, that's actually a good thing. You're going to need a very small coin.
Just heat the room and every object in it including the coin to body temperature, and then there will be no net transfer to heat to or from any object.
But what about the fact that the heads and tails side have different engravings, meaning photons will hit them at a different angle, and that will produce a bias so imperceptibly small that it wouldn't even affect a single flip if you flipped a coin from now until the heat death of the universe? Better flip in a pitch black room just to be safe!
These ever more ridiculous scenario are just that - ridiculous. Using von Neumann's algorithm and the same starting conditions for each flip is all that is needed to product a complete random string of bits. If someone is genuinely concerned about the different sides of the coin having a difference of a one degree and that somehow heating up the adjacent air enough to bias the flip, then they should be absolutely terrified of the security of literally everything else in their life, which won't be as random as this.
But what about the fact that the heads and tails side have different engravings, meaning photons will hit them at a different angle, and that will produce a bias so imperceptibly small that it wouldn't even affect a single flip if you flipped a coin from now until the heat death of the universe? Better flip in a pitch black room just to be safe!
These ever more ridiculous scenario are just that - ridiculous. Using von Neumann's algorithm and the same starting conditions for each flip is all that is needed to product a complete random string of bits. If someone is genuinely concerned about the different sides of the coin having a difference of a one degree and that somehow heating up the adjacent air enough to bias the flip, then they should be absolutely terrified of the security of literally everything else in their life, which won't be as random as this.
pennies these days are made of mainly zinc like 95 percent with a copper coating. zinc is not quite as good of a heat conductor as copper.
lets say room temperature is 85 deg F and your hand is 95 deg F. That's a temperature differential of 10 degrees. You have the coin sitting in the palm of your hand with one face exposed to 95 deg F and the other side exposed to room temperature. There is going to be some temperature differential when you actually toss the coin and the sides will not get into thermal equilibrium before the coin lands.
Okay, I'll bite. But in normal units. Let's assume there's a 1oC (or 1K) temperature difference between both sides of the penny. And let's assume it's made of 100% zinc (Wiki: 97.5% Zn, 2.5% Cu).lets say room temperature is 85 deg F and your hand is 95 deg F. That's a temperature differential of 10 degrees. You have the coin sitting in the palm of your hand with one face exposed to 95 deg F and the other side exposed to room temperature. There is going to be some temperature differential when you actually toss the coin and the sides will not get into thermal equilibrium before the coin lands.
The diameter is 19.05 mm, and it's 1.52 mm thick (Wiki). That means the surface area is 285 mm2. The thermal conductivity is 112.2 W/mK.
It's been a while, so I had to look it up:
Quote from: Byjus.com
The thermal conductivity of a material is described by the following formula:
K = (QL)/(AΔT)
Where,
K is the thermal conductivity in W/m.K
Q is the amount of heat transferred through the material in Joules/second or Watts
L is the distance between the two isothermal planes
A is the area of the surface in square meters
ΔT is the difference in temperature in Kelvin
So:
K=112.2 W/mK
Q=
L=0.00152 m
A=0.000285 m2
ΔT=1 K
That means:
Q = K * A * ΔT / L = 112.2 * 0.000285 * 1 / 0.00152 = 21 W.
This confirms what I expected: you'll need to transfer massive amounts of energy through a penny to get a small temperature difference between both sides.
The specific heat of Zinc is 0.387 J/g K. A penny weights 2.5 g. That means adding 21 W for 1 second would be enough to raise the temperature of a penny by almost 21.7 K. It's safe to say you won't transfer 21W from your hand or a slightly warm surface into a penny, and it's safe to say the heat transfer inside the penny is large enough to keep both sides at almost exactly the same temperature.
you would need a device that can measure the temperature of each side of the coin simultaneously.
There won't be any temperature difference between sides, metals are excellent heat conductors.pennies these days are made of mainly zinc like 95 percent with a copper coating. zinc is not quite as good of a heat conductor as copper.
lets say room temperature is 85 deg F and your hand is 95 deg F. That's a temperature differential of 10 degrees. You have the coin sitting in the palm of your hand with one face exposed to 95 deg F and the other side exposed to room temperature. There is going to be some temperature differential when you actually toss the coin and the sides will not get into thermal equilibrium before the coin lands.
So what i'm saying is the way you hold the coin and how long it is in contact with your hand and in what way those things can have an effect. probably not large ones but i haven't tested it.
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