LavaRnd: A Open Source Project for Truly Random Numbers

Phil Windley writes "Truly random numbers are crucial to good encryption. Most people have heard of Silicon Graphic's use of Lava Lamps to generate random numbers. There were some problems: it required special SGI hardware and software along with six lava lamps, and the solution wasn't portable. But the biggest drawback was that SGI patented the idea so it wasn't freely available. Now, some of the scientists behind the SGI random number system have create LavaRnd, an open source project for creating truly random numbers using inexpensive cameras, open source code, and inexpensive hardware. The system uses a saturated CCD in a light-tight can as a chaotic source to produce the seed. Software processes the result into truly random numbers in a variety of formats. The result is a random number that is crytographically sound, ranking at the top of its class in the NIST 800-22 Billion bit test. Its even portable, so the truly paranoid can take it with them when they travel."

Comments

Bizarre sequences of random numbers

[umrgregg]

I just used LavaRnd's Lotto Number Generator with default values and it returned:

1, 2, 3, 4, 5, 6

Talk about random...

Anyway, my idea for an open source number generator is to have people on slashdot post the first number that comes to mind in this thread. I don't know if it could get more random.... (patent pending)

Re:Bizarre sequences of random numbers

[wfberg]

Anyway, my idea for an open source number generator is to have people on slashdot post the first number that comes to mind in this thread. I don't know if it could get more random.... (patent pending)

69

Re:Bizarre sequences of random numbers

[inertia187]

You think that's bizarre, I got "503 Service Unavailable." How do I use that as a lotto number??

Re:Bizarre sequences of random numbers

[Elbelow]

I just used LavaRnd's Lotto Number Generator with default values and it returned:

1, 2, 3, 4, 5, 6

Well, in a truly random sequence, this combination is just as likely as any other... :-)

Re:Bizarre sequences of random numbers

[42forty-two42]

Be sure to filter out all instances of '42' in the output.

Re:Bizarre sequences of random numbers

[drewbradford]

What strikes me as odd is that the term "random numbers" is still used even among us, the excessively nerdy. Of course, pseudo-random is better, but I think that "unpredictable" would be the best term.

All numbers generated are based on something, so they'll never be truly random. The best that we can do is make them truly unpredictable, such that it cannot be determined which specific factors they are based on.

===
http://www.drewbradford.com/

Re:Bizarre sequences of random numbers

[batkins]

Yeah, but pseudo-random numbers are, by definition, predictable.

Re:Bizarre sequences of random numbers

[Guano_Jim]

That sounds like the combination an idiot would have on his luggage!

Re:Bizarre sequences of random numbers

[itwerx]

Amazing how many /.'ers dunno what 42 is. :)

It's the Answer to the Question...

Re:Bizarre sequences of random numbers

[malfunct]

What always bothers me is when people want uniformly distributed random numbers. I know why its valuable but if you make sure that your numbers are uniformly distributed they aren't really random anymore.

Its just as likely to get all 0's or all 1's as it is to get any other single random number and yet 9 out of 10 people would probably say all 0's or all 1's isn't a random result, even when it comes from a random source.

I guess the big misunderstanding is that once you have a number, its not random, you know what it is. A random pattern is probably better defined as one you can't predict, and once you have it, recreating it with the same process is not likely.

Re:Bizarre sequences of random numbers

[MacJedi]

What always bothers me is when people want uniformly distributed random numbers. I know why its valuable but if you make sure that your numbers are uniformly distributed they aren't really random anymore.

I'm guessing that this isn't exactly what you wanted to say and it just came out wrong, but why are uniformly distributed random numbers not random? True, you have knowledge about the distribution that the random numbers came from, but you still would never be able to predict the next number. And, bottom line, if you can't predict the next number IT REALLY IS RANDOM.

/joeyo

Re:Bizarre sequences of random numbers

[pclminion]

What always bothers me is when people want uniformly distributed random numbers. I know why its valuable but if you make sure that your numbers are uniformly distributed they aren't really random anymore.

You don't understand what is meant by "uniformly distributed." Say you have a uniform random variable taking on the values 1..10. A "uniform random variable" means that each possible outcome has an equal probability of occurring. It doesn't mean that there must necessarily be equal numbers of 1,2,3,4, etc. in the output.

Imagine the previous random source generating two sequences. The first is [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]. The second sequence is [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]. How much less likely is it to generate the second sequence than the first one? The answer is, it is no less likely. Both sequences are equally likely. This is the meaning of a "uniform source." It certainly doesn't mean that sequences such as [1, 1, 1, ...] cannot occur!

9 out of 10 people would probably say all 0's or all 1's isn't a random result, even when it comes from a random source.

They probably would say that, but they'd be wrong. People have major misconceptions about randomness. If a random source generates the sequence [1, 6, 3, 3, 8, 2] people will say "Ho hum." If the same source outputs [1, 2, 3, 4, 5, 6] people all of a sudden get interested and say "I wonder what's going on." There's nothing going on. The random source doesn't care whether your brain wants to ascribe some special meaning to the sequence [1, 2, 3, 4, 5, 6]; it generated it mindlessly, and your human tendency to pick out patterns has kicked in. You are imposing your own order on it, when no real order exists.

Re:Bizarre sequences of random numbers

[Asprin]

I've had a gripe about random number research since I sat in on a guest colloquium on this topic in the late 80's.

The word "random" cannot describe a result, only the process that generates that result. A truly random generator should be entirely capable of generating such patterned sequences like 1,2,3,4,5,6; although it should select them no more or less than any other sequence you care to consider interesting.

Put another way, every seemingly random sequence will mean something very special to somebody eventually.

If you set out with the assumption that such patterned results must never occur, then you have biased your generator against certain results, and your generator is therefore, BY DEFINITION, not random. In fact, a predisposed inability to generate such sequences should be grounds for discrediting a generator.

This drove me crazy (like a splinter, not like explaining Scott Baio's career) all through the lecture and beyond.

But, alas, we live in the world of the human, where we have sex, UFOs, attorneys, crop circles, knee-jerk reactions to politically charged topics and Mighty Mouse. In *THIS* world, the sequence 1,2,3,4,5,6 **IS** special, because we are hopelessly devoid of really genuinely new ideas. Just like computers work be copying, we work by finding and engaging patterns.

So, I decided that randomness has nothing to do with it. Their real goal isn't a flat probability function, but throwing out the first few percent of possibilities the bad guys are likely to try first so they are forced to think harder.

I also decided that when cryptography and number theory people say "random", they really mean "unpredictable" or "unpatterened" and I should just leave it at that. I just wish they hadn't been so careless in choosing language to describe what they were doing that has such a confusingly similar meaning outside their field.

Re:Bizarre sequences of random numbers

[Just Some Guy]

I understand what you're trying to say, but you're wrong. Nature is random. Heisenberg showed that not only can you not predict the occurrence of an event, but that if you get enough information to try to do so, then the event itself will happen differently than you would predict - and the difference is also random.

Look at atomic decay. You can predict fairly well how fast a large sample of a radioisotope will decay, but it is flat-out impossible to predict when any given atom will decay. That's about as random as you can get.

Re: Bizarre sequences of random numbers

[Black Parrot]

> What always bothers me is when people want uniformly distributed random numbers. I know why its valuable but if you make sure that your numbers are uniformly distributed they aren't really random anymore.

Sure they are. There's a difference between "randomness" and "distribution". You could have random numbers with a uniform distribution, a gaussian distribution, an exponential distribution, some bimodal distribution, etc., and they would still be random.

But it's really convenient to have a RNG with a uniform distribution, since you can easily transform numbers drawn from that distribution to some other arbitrary distribution by taking f(x) with the desired f() and an x drawn from the uniform distribution.

BTW, "uniform distribution" doesn't mean that you get the same number of occurences of each number in the range; it only means they have the same probability of occuring. (OK, that distinction gets a bit tricky when you're talking about pseudo-random numbers, but let's pretend we're talking about genuinely random numbers.)

> Its just as likely to get all 0's or all 1's as it is to get any other single random number and yet 9 out of 10 people would probably say all 0's or all 1's isn't a random result, even when it comes from a random source.

Yeah, but that's because we intellectually identify those numbers as "special", when they aren't really. For instance, people would probably think the numeric representation of their birthdate was special, though someone else might think it a perfectly random number. Strictly speaking, randomness has nothing to do with the importance humans assign to the result.

> I guess the big misunderstanding is that once you have a number, its not random, you know what it is.

Yes, the a posteriori probability of an event, given that the even happened, is always one. Pseudoscientists are fond of constructing probability arguments that they think should be convincing, not realizing that they are just painting a bull's-eye around wherever the arrow happened to strike.

> A random pattern is probably better defined as one you can't predict, and once you have it, recreating it with the same process is not likely.

For most uses we would want to say that "you can't predict" means that all possible patterns are equally likely, i.e. that betting on one has the same expected pay-off as betting on any other, at least if we're talking about a uniform distribution. And as for re-creation, we usually want sequentially generated patterns to be independent, i.e. that knowing what has been produced in the past does not help you predict what's coming up next. In particular, if your generator produced pattern z last time, the probability of producing z next time is still the same as the probability of producing any other pattern.

Any time there is a preferred way to bet, whether considering the past or not, it means that your generator is biased in ways that you probably don't want for a basic RNG. If you want biases, introduce them by filtering the number produced by a RNG with a uniform distribution.

Re:Bizarre sequences of random numbers

[letxa2000]

I think the best way to generate random numbers is to somehow "digitize" SCO's daily claims. They seem about as random and non-predictable as any random number generator I've seen. :)

Re:Bizarre sequences of random numbers

[MarkGriz]

"idiot = i*i*dot = -dot"

Wasn't that the inspiration for slashdot?

"MinusDot??? That's a stupid name"
"ok, how about Slashdot"
"Yeah, much better."

Re:Bizarre sequences of random numbers

[Ed Avis]

Huh? Pseudo-random numbers are those that follow a sequence you can predict, if you know how the generator works and what its internal state is.

Random numbers are those you cannot predict. I'm no physicist, but I think quantum theory says that many natural events occur randomly - that is, there's no way of knowing which slit a photon will 'choose' to go through, and it isn't particularly 'based on' anything except a 50/50 probability.

All numbers generated are based on something, so they'll never be truly random.

So then if all current sources of numbers are not random, what _would_ meet your definition of the word 'random'?

Re:Bizarre sequences of random numbers

[Ed Avis]

A number is not 'random'. There is no test you can apply to determine that 25 is random, while 44 is not. Randomness is not a property of individual numbers, it is a property of the number generator or source.

So when people say 'a random number' they really mean 'a number drawn from a random source'.

You're talking about Kolmogorov complexity, I think - the complexity of some data is the length of its shortest description. But even there you have to agree what language the description will be in. You could define a language where 18282822 is represented by the symbol 'A' and any other number is represented by itself.

Re:Bizarre sequences of random numbers

[Jack Schitt]

here you go... totally random... type your credit card number and social security number into the forum. wait a couple of months. then look at the dollar amounts on your credit statement...

Re:Bizarre sequences of random numbers

[Notre97]

Reminds me of this old Dilbert comic:
http://www.wps.k12.va.us/jhhs/math/humor/comics/co mputer/random.html

Re: Bizarre sequences of random numbers

[Black Parrot]

> > Yeah, but that's because we intellectually identify those numbers as "special", when they aren't really.

> Actually, those numbers are special in a particular way that makes them not random. They have a low Kormalagorov Complexity, so they're highly compressable. Good random data should be uncompressable.

Actually it's the representation of those numbers that is compressible, which is irrelevant to the randomness of a sequence of numbers.

For instance, the number 1,111,111,111 has a compressible base-10 representation, but if you were working in base 1,111,111,112 it would have an atomic, uncompressible representation. And that distinction is irrelevant to the question of how often it shows up in a random sequence.

Re:Bizarre sequences of random numbers

[NonSequor]

For those who don't know, the Kolmogorov complexity of some mathematical object with respect to a given universal computer (ie some sort of machine or language that is Turing complete) is the length of the shortest program for that computer which outputs the object. Actually, when working with Kolmogorov complexity, the universal computer being considered isn't really important. Since you can use any universal computer to emulate any other universal computer, then if you know the Kolmorogov complexity of an object under one computer is K then you know the Kolmogorov complexity of the object under another computer is less than or equal to K+c (where c is the size of a program to emulate the first computer in the second one).

These constants aren't of much concern since they are independent of the objects being studied (that's what makes them constants!). No one actually tries to figure out what exactly the Kolmogorov complexity of an object is, since it would be a total bitch to try to prove that a given program is the shortest one there is and as a result of the halting problem, no program can compute the Kolmogorov complexity of an arbitrary object. Instead, one generally tries to find an upper bound on the Kolmogorov complexity of an object which is valid for any computer.

Re:Bizarre sequences of random numbers

[Ed Avis]

When working with K. complexity in general the universal computer doesn't matter much, but if you try to pick a particular number or message out of the air and work out the complexity of that it does matter. You could define a Turing machine with one extra instruction that prints out the complete works of Shakespeare, and then the complexity of that particular string would be very low. But such a special machine would not help you at all if trying to reduce the complexity of strings in general. The point is that you have to be very careful when picking a single number and trying to talk about complexity or randomness after the fact. Normally you'd worry about these things for numbers to be drawn from a particular distribution, not just one number you picked out of a hat (with also the liberty of picking a particular computational model out of a hat).

Re:Bizarre sequences of random numbers

[kasperd]

There is no test you can apply to determine that 25 is random, while 44 is not.

Read the definition again, it actually does make some sense. The number 7^99 is not a random number because the description I just wrote is a lot shorter than the number itself. The number 61070941271139577504711647465813663675921309412553 1498031084978534953383702400017179 OTOH has the same length as the previous number, but I have no shorter description of this number. In fact I did get it from a random source, but I have no way to prove that this is a random number.

I can see it now...

[Anonymous Coward]

"But, sir, I need this lava lamp for my cubicle! It's required for encrypting our company's secrets. I also need the black light, for, uh... stopping pop-ups."

truly random numbers in a variety of formats

[hackstraw]

... "truly random numbers in a variety of formats" ...

Think about that for a second.

Sourceforge Copy

[Anonymous Coward]

Site's already /.'ed.

You can nab the code off sourceforge though:

http://sourceforge.net/projects/lavarnd

Analog is the key

[whatch durrin]

Isn't the key to generating a truly random number having an essentially analog source?

That being said, could you not measure the exact voltage on a CPU, or the ambient temperature to several decimals, or other environmental conditions, then use that as a base?

Re:Analog is the key

[hackstraw]

Isn't the key to generating a truly random number having an essentially analog source?

Not necessarily. Its best to have some kind of chaotic source. Also, being that the world we live in is analog, not digital, aren't all sources analog in nature?

An interesting source for chaotic conditions would be weather. If one could pick a seed from an arbitrary date in history and a seed for some arbitrary extra weather condition (increase/decrease temp, humidity, pressure, etc) and feed that back into a weather simulator, you should get some nice chaos pretty quickly.

Re:Analog is the key

[MxTxL]

Isn't the key to generating a truly random number having an essentially analog source?

Well, no. Just a strict analog source would be good if you could poll it at random intervals. Unfortuantely, most regular analog sources follow a sine curve when you get to looking closely enough. Temperature will tend to fluctuate within a X of a degree around a certain temperature. No matter what resolution you look to, it will do the same thing, go a little up, and a little down. Basically following a sine curve. Polling this at random to some number of decimals would be fine, but you can't define 'at random'... which is the whole point. If i told my computer to get the temperature at regular intervals, it would get predictable numbers.... and you can't use random intervals, if you had those you wouldn't have to go through this!

Re:Analog is the key

[FroMan]

Actually, I think you would wind up using only a single bit at the least significant bit end of the value of the temp. You wouldn't use the whole value.

This of it this way:

Temp:
00110101.10100111
00110101.11000101
001 10101.10100110
00110101.10110101
00110101.101010 10
00110101.10100010
00110101.10101101
00110101 .10110101

Each of the temp reading wouldn't be used, but your random values would be

11010011

You throw away all the extra data at the full value and only take the least significant bit as it would be the least stable of the values.

You call that Pi?

[Anonymous Coward]

That ain't Pi! This is Pi!

3.141592653589793238462643383279502884197169399375 1058209749445923078164062862 08998628034825342117067982148086513282306647093844 6095505822317253594081284811 17450284102701938521105559644622948954930381964428 8109756659334461284756482337 86783165271201909145648566923460348610454326648213 3936072602491412737245870066 06315588174881520920962829254091715364367892590360 0113305305488204665213841469 51941511609433057270365759591953092186117381932611 7931051185480744623799627495 67351885752724891227938183011949129833673362440656 6430860213949463952247371907 02179860943702770539217176293176752384674818467669 4051320005681271452635608277 85771342757789609173637178721468440901224953430146 5495853710507922796892589235 42019956112129021960864034418159813629774771309960 5187072113499999983729780499 51059731732816096318595024459455346908302642522308 2533446850352619311881710100 03137838752886587533208381420617177669147303598253 4904287554687311595628638823 53787593751957781857780532171226806613001927876611 1959092164201989380952572010 65485863278865936153381827968230301952035301852968 9957736225994138912497217752 83479131515574857242454150695950829533116861727855 8890750983817546374649393192 55060400927701671139009848824012858361603563707660 1047101819429555961989467678 37449448255379774726847104047534646208046684259069 4912933136770289891521047521 62056966024058038150193511253382430035587640247496 4732639141992726042699227967 82354781636009341721641219924586315030286182974555 7067498385054945885869269956 90927210797509302955321165344987202755960236480665 4991198818347977535663698074 26542527862551818417574672890977772793800081647060 0161452491921732172147723501 41441973568548161361157352552133475741849468438523 3239073941433345477624168625 18983569485562099219222184272550254256887671790494 6016534668049886272327917860 85784383827967976681454100953883786360950680064225 1252051173929848960841284886 26945604241965285022210661186306744278622039194945 0471237137869609563643719172 87467764657573962413890865832645995813390478027590 0994657640789512694683983525 95709825822620522489407726719478268482601476990902 6401363944374553050682034962 52451749399651431429809190659250937221696461515709 8583874105978859597729754989 30161753928468138268683868942774155991855925245953 9594310499725246808459872736 44695848653836736222626099124608051243884390451244 1365497627807977156914359977 00129616089441694868555848406353422072225828488648 1584560285060168427394522674 67678895252138522549954666727823986456596116354886 2305774564980355936345681743 24112515076069479451096596094025228879710893145669 1368672287489405601015033086 17928680920874760917824938589009714909675985261365 5497818931297848216829989487 22658804857564014270477555132379641451523746234364 5428584447952658678210511413 54735739523113427166102135969536231442952484937187 1101457654035902799344037420 07310578539062198387447808478489683321445713868751 9435064302184531910484810053 70614680674919278191197939952061419663428754440643 7451237181921799983910159195 61814675142691239748940907186494231961567945208095 1465502252316038819301420937 62137855956638937787083039069792077346722182562599 6615014215030680384477345492 02605414665925201497442850732518666002132434088190 7104863317346496514539057962

I'm going to get modbombed to hell, but...

[Anonymous Coward]

I don't want to start a holy war here, but what is the deal with you SGI lava lamp fanatics? I've been sitting here at my freelance gig in front of a lava lamp (SGI LavaRnd lamp) for about 20 minutes now while it attempts to create me a 17 Meg file of random numbers. 20 minutes. At home, the lava lamp I got from my mom, which by all standards should be a lot slower than this SGI lamp, the same operation would take about 2 minutes. If that. In addition, during this random number generation, Netscape will not work. And everything else has ground to a halt. Even Emacs Lite is straining to keep up as I type this.

I won't bore you with the laundry list of other problems that I've encountered while working on various SGI lava lamps, but suffice it to say there have been many, not the least of which is I've never seen a SGI lava lamp that has run faster than its 1960s counterpart,despite the SGI lamp's smaller viscosity. My lamp with runs faster than this SGI lamp at times. From a productivity standpoint, I don't get how people can claim that the SGI LavaRnd is a "superior" machine.

SGI addicts, flame me if you'd like, but I'd rather hear some intelligent reasons why anyone would choose to use a SGI over other faster, cheaper, more stable systems.

First,

[EnderWiggnz]

...

start with radioactive material... ...

Does it

[Timesprout]

A Open Source Project for Truly Random Numbers

cause random n's to be dropped from sentences ?

What's the probability..

[dlosey]

Its even portable, so the truly paranoid can take it with them when they travel.

that if one were truly paranoid they really travel in this day and age?

A Slashdot secret revealed.

[AtariAmarok]

I always wondered what was behind some of the moderation decisions I've been seeing!

other semiconductors

[fortunatus]

audio circuits often use diode junctions in reverse-breakdown mode as a source of "white noise". couldn't we computer folks do the same? seems a similar idea to the the dark CCD technique.

Re: other semiconductors

[Black Parrot]

> audio circuits often use diode junctions in reverse-breakdown mode as a source of "white noise". couldn't we computer folks do the same? seems a similar idea to the the dark CCD technique.

I think there are already a lot of solid-state solutions out there that use thermal noise to generate random bits. The lava-lamp solution and its derivatives sound like a lot of fun geeky fooling-around, but ultimately seem to be a solution in search of a niche.

A mic listening to the environment?

[van der Rohe]

I'm not a math guy. At all.
So forgive me if this is dumb or not the right idea.
But why not just use a sensitive microphone listening to the ambience in a room to "seed" some sort of algorithm?

Re:A mic listening to the environment?

[haystor]

You are correct that white noise can produce appropriately random numbers.

The problem is that for encryption purposes you may need some huge random numbers. If you want to do that from an analog solution you'll have to take your samples closer and closer together, until the numbers become less random. If you start sampling sound 1 million times a second, any two values next to each other my be really close and actually predictable.

Re:A mic listening to the environment?

[rjoseph]

Right, and then there's the problem of isolation. The reason that the camera in this project is in a sealed box is because that if you are going to try and actually prove mathematically that the randomness of the system is truly random, it needs to be in isolation, outside of the realm of any intervention.

Therefore, just putting a mic in a room allows for the possibility that the seed can be manipulated, although figuring out what sounds to make in the room to do so in a predicatable manner is incredibley difficult, it's still possible and therefore not theoretically sound.

Re:A mic listening to the environment?

[molo]

Good idea, but insecure. What happens when I put a tuning fork next to it? That provides order, and order = no entropy = no randomness. Its too easy to tamper with, and a motivated attacker could limit or even predict the output.

You're on the right track though. Its an analog source, just like the lava lamps.. but how the heck are you going to tamper with a lava lamp? :)

-molo

Re:A mic listening to the environment?

[Suicyco]

Because sound is not random at all. White noise is, but how often do you hear that? Not often. Voices, cars driving by, phones ringing, all of these are patterns. Patterns lead to cracks in the numbers that can be culled for weaknesses in the algorithm. This in turn leads to knowledge of what algorithm is being used, which in turn leads to a directed cryptanalysis of the data, exactly what true random numbers are meant to avoid.

Even using mouse clicks, keystroke times, etc. is not random. Thats why its called "pseudo-random". Processing normal everyday sound through a PRNG (pseudo random number generator) is still only pseudo, not real.

People have been working on this problem for decades. Trust me, what you are asking about has not only been tried, but been used and even attacked.

Re:A mic listening to the environment?

[Phronesis]

Sound does not give white noise, but thermal noise on a perfect resistor is perfectly white. An imperfect resistor can produce an excellent approximation of white noise within a fairly large bandwidth.

As to working on the problem for decades, excellent commercial analog white-noise generators have been available for half a century or more. The only problem is making a very cheap white noise source that can be digitized conveniently.

*That* won't work...

[siskbc]

Anyway, my idea for an open source number generator is to have people on slashdot post the first number that comes to mind in this thread. I don't know if it could get more random.... (patent pending)

The only numbers that generates is 42,69,503,and 23. I figure in 2 more posts you might get 17 too.

I have the most portable solution...

[PrimeWaveZ]

For generating random numbers: A quarter in my pocket and a lot of free time.

what about audio output?

[mbreitba]

I had a friend that 5 or 6 years ago used the "white noise" from his SB 16 to generate random numbers. Wouldn't this be much more portable than a lava lamp? -Matt

Lava lamps?

[johnisevil]

Lava lamps? Damn hippies.

Can't be done.

[Chess_the_cat]

Unless the random-number generator is built outside of our Universe, it can't generate truly random numbers. Only pseudo-random ones. As it stands, there will always be something influencing the result. Fortunately for us, pseudo-random numbers are impossible to differentiate from random ones and are random enough to serve our purposes anyway.

Re:Can't be done.

[nat5an]

Hey! Quit spoiling the party with actual facts!

Seriously though. Your point is valid. In our universe, (good) psuedorandom numbers are just as random as anything else in the universe (that we consider random). The real problem is that people look for a distinction between random and pseudorandom when none exists.

Re:Can't be done.

[CyberGarp]

Ahh contrair, you assume hidden variables young grasshopper. Even Einstein had trouble believing that quantum physics depended on randomness. The hidden variable theory has been attacked from many angles, and noone has been able to prove yet that there are hidden variables, in fact there is much evidence that quantum mechnics depends on randomness.

Re:Can't be done.

[alanh]

You're wrong. Quantum mechanical effects can be truly random. Nuclear decay is a good example of this.

Set up a piece of radioactive material next to a geiger counter, plug your geiger counter into your PC and you can generate all the random numbers you want.

Incredible!

[mblase]

I just used LavaRnd's Lotto Number Generator with default values and it returned:
1, 2, 3, 4, 5, 6

That's the same combination I use on my luggage!

cool idea for a case mod

[kisrael]

going back to the original idea, how cool would it be to have a lava lamp inside the case, maybe helping out all those heatsinks by converting heat into lava-moving power...with a window so you can see it as it generated all the random numbers you needed.

"Anyone who considers arithmetical methods of producing random numbers is, of course, in a state of sin."
--John von Neumann

Truly random numbers

[cheesekeeper]

Truly random numbers R LAME. LOL l337 HAX0Rs use the number "7" for every random seed. You can't tell if it's a seven or a 't'! Encrypshun R 4 DUMMMIES!

</joke>

Study Chaos

[tshak]

Nothing is truly random about a lava lamp, or even the fractals on a leaf. "Randomness" as we understand it has always been about complex order and large numbers. Meaning, it's too complex for us to see the pattern and the statistical possibility of numbers occuring in a measurable pattern over time is extremely low.

Apple ][ used keypress timing seeds

[call -151]

The Apple ][ computers used the pause between keystrokes, measured much more precisely than necessary and disregarding all but the last 8 bits, as an attempt at an analog random number seed for their psuedorandom number generator. Very simple and effective and I haven't seen many implementations of better systems around. One side effect was that if you had a program which ran off the boot disk with no keystrokes, it would do the same thing every time, no matter how improbable that was...

123456?

[dark&stormynight]

123456? That's the combination of my luggage. I need new luggage!!!

The random number seems to be...

[Dog and Pony]

503 ;-)

Paranoid

[Quill_28]

>so the truly paranoid can take it with them when they travel."

pfftt, like there is anyone on Slashdot that is paranoid.

What about double-slit experiment?

[dschuetz]

I've always wondered if the double-slit experiment, in a particle mode, would be a good way to generate random numbers.

The phenomena (for those unfamilar with it) is putting two closely-spaced slits in a piece of paper and then shining a light through it. You end up with a spreading fringe of light and dark patterns, as the light waves coming through the slits interfere with each other.

Where it gets spooky is when you drop the light source down to where it emits photons one at a time -- they *still* interfere with each other, even though there aren't any other photons present at any given point to interfere with.

Anyway, I seem to recall that the place where each photon ends up is random. So why not put a low-power, stream-of-single-photons light source on one side of the double-slit, and a pair of sensors on the other side? Label one sensor "0" and the other "1" and interpret the strings as binary numbers. Convert (and optionally send them through a bit blender) and you're done.

I'd think this could be manufactured in a small chip-like package, and made a standard motherboard component.

Has anyone investigated this approach? If so, I'd be curious to hear what their results were (and if it turns out not to be as random as one would like).

Re:What about double-slit experiment?

[zeotherm]

Where to begin... For starters, the double slit experiment, to see the neat effects of single electron interference, must be done in a vacuum. The electorns must not be influenced by anything else at all, like air/gas molecules. Also, it must be done at temperatures near absolute zero, where the thermal bath of the environment doesn't wash out the quantum effect you are talking about... Just not possible on a portable system...

ObHHG

[red floyd]

, no matter how improbable that was

Ford, you're turning into a penguin. Stop it.

Why not use a simple ZENER DIODE

[melted]

This will produce a truly random signal (white noise) which is completely unpredictable. $0.05 solution + $2-5 in external components is all you need.

Re:Expensive!

[Knight2K]

I'm not a radio expert... but theoretically, couldn't a system like that be attacked by beaming out a strong known signal with limited range on the frequencies (or possibly spill across a broad spectrum) utilized by the random system? Then the attacker could guess the random series since it forced the generator to use a known seed.

At least an optical system is tougher to interfere with since the local user knows what the camera is looking at.

Arbitrary, not random

[The Famous Brett Wat]

which of the following isn't a random set of numbers

Answer: none of them were random; all of them chosen by you off the top of your head. There are important mathematical differences between these two cases. What you have given is sets of "arbitrary" numbers, rather than "random" numbers.

Now, if you'd asked which of the sets could be generated randomly, then the answer is all of them, given a generator function with the correct output range.

Good ole' radiation

[Fishead]

What about radiation? I remember way back in physics using a piece of radioactive material in front of a sensor connected to a computer to generate a large number of random numbers. It would be fairly easy to use a small piece of Californium such as is in a smoke detector connected to a sensor. The time between radioactive particles should be random enough and it is small enough to fit anywhere.

Re:PiPi

[generic-man]

Pi is exactly 3!

Randomness based on loss

[phorm]

How about transmitting a signal through some form of changing medium? Really, with the lavalamp approach, all that fancy webcam stuff isn't needed. How about just using a lavalamp type setup with various different floating substances (density, reflectiveness, etc) and shooting some for of beam through it at various areas - calculating the number based on the returned signal?
You don't really need a lavalamp for this either, passing an electrical signal over a short arc-gap, perhaps filling with a changing substance would probably also product random voltage fluxation.

Of course, the real issue is making randomness with a large range (1-100% with many many decimal points) and a large enough variability (that is, any decimal number between 1-100% having an equal opportunity for occuring at any particular interval).

I'm thinking that in electrical and biochemical reactions there would also be a lot of randomness, the wide-universe and entropy and all considered?.

whatch_durrin vs. VIA

[henele]

From an article on VIA's Antaur processor...

"The Antaur also ships with Via's "Padlock" feature, a random-number generator that actually produces "true" random numbers by measuring random components of the thermal energy produced by the chip, according to its designer, Glenn Henry. RNG generators can be used to develop true randomized cryptographic keys."

Re:Analog is NOT the key

[slimak]

Actaully it can't change instantaneously (in no time), which shouldn't matter since you can't sample this analog source infinitely fine anyway. Provided your sampling period is large enough the samples could change from lowest to highest in a single sample.

Paranoid??

[ocie]

the truly paranoid can take it with them when they travel.

Oh, that just what you'd want us to do isn't it???

Different objectives

[m11533]

The original motivation for random number generators was simulation. One of the early mainframes, and I am afraid I forget which one, included a true random number generator. It was an unexpected disaster, totally unusable for simulation and other then-state-of-the-art users of random numbers. They were "too random".

It turns out that for an experiment to be useful it need to be repeatable. Thus, it was critical that users be able to repeat the sequence of "random" numbers. Thus the reason why all random number mechanisms permit you to set the seed... otherwise they could just use a sufficiently random seed and life would be good.

Another aspect of random number is that they must not only be "random", but they need to have a well defined distribution over the range of possible values. You might assume it is desirable to have a linear distribution, which IS useful in some settings, but other distributions ("bell curve", and exponential come to mind) are also extremely useful.

IF one has a real need for truly random numbers, the source for those number does need to perform to a certain distribution over the range of possible values. And it can not be used to the exclusion of the existing techniques which have been extremely useful in their intended problem domains. This is really just another case of a good solution in one problem domain being used in another without its underlying foundation being examined for applicability to that new problem domain.

Re:Different objectives

[zorander]

Simulation != Cryptography

Uh.

[radiumhahn]

I would set up my computer to use one of those tiny cameras that we keep seeing in spam, but I don't think I should rely on hot babes sneaking into my apartment and dancing nude on my bed to generate random numbers. It is a great idea tho!

[Patent Pending]

Re:This _is_ crazy...

[insecuritiez]

The system you propose is a form of one time pad. While it works in theory, it is not the application needed here. Random numbers are needed in streams where there can be no pattern known or logical pattern findable. How many ways can you think to scratch a CD? Up and down, right and left, circles? With this sort of information you could start to predict the general "form" of the number. Besides, when you need a stream of numbers it needs to change over time. The CD is scratch once use once.

Cryptographic Strong Random Number Generators

[plcurechax]

When designing and building a physical cryptographic strong random number generator (CSRNG, not CSPRNG) you are looking for many things including:

* a uniform or near uniform distribution of the output.
* it must be unpredictable
* it should be very hard / impossible for attacker to influence the output of the CSRNG.

The first two are reasonably easy with physical RNG, but the last one is the kicker when it comes to actually implementing the CSRNG.

The attacker shouldn't be able to influence it by poking a pin-hole in the case (of a light sealed chamber around the CCD), or putting a heat source next a lava lamp (so the goo stays at the top)

Silly overkill

[Phil Karn]

Generating random bits with a lava lamp has always seemed like silly, impractical overkill to me. For years, the Linux kernel has had the /dev/random driver that distills entropy from external events, and now it can be seeded by the hardware random bit generators found in many modern CPUs.

Nearly every PC also has a sound interface that could also be used as a rich source of random seed bits. You don't even need a microphone; just crank up the gain and digitize the analog noise in the microphone preamp.

This really isn't hard. OBG.

[Jonsey]

All you need a is good source of Brownian motion. Say a good hot cup of tea...

"True" randomness is unattainable

[Stuntmonkey]

creating truly random numbers using inexpensive cameras

Fussy nitpick:

As a matter of principle we shouldn't talk about "true" random numbers. Even if you have a source of quantum randomness (the best you can do), in any practical scheme there will always be differences in how 0's and 1's are detected. The impact of these differences can be minimized through careful design, but they will always be there and will cause a departure from an exact 50/50 split of 0's and 1's.

For example, an attenuated laser passing through a simple 50/50 beamsplitter and into 2 single-photon detectors is far better than a lava lamp. But no beamsplitter is exactly 50/50, and this will cause an excess of 0's or 1's. (You could adjust the detection efficiency or optical alignment of the detectors to compensate, but the point is that this is a manual adjustment that will never result in exactly zero bias.) And no amount of algorithmic hashing or obfuscation can eliminate this bias (although it may reduce it significantly).

It will always be the case that any practical system for generating bit sequences of length N will never generate them with a frequency of exactly 2^(-N) each (in the limit of an infinite number of trials), and with zero correlation between successive bit sequences. "Truly" random numbers are an unattainable goal.

Truely paranoid indeed

[t_allardyce]

"Its even portable, so the truly paranoid can take it with them when they travel."

Which one of this is the most likely: - someone manages to get your low-class 'pseudo' random number by extrapolating the exact time of the system clock and the contents of your memory etc. and running it through the algorithem. Someone manages to predict or find your mouse movements by the indents on your mouse mat and the use this to get the same random number you created by moving the mouse in the box. Someone looks over your shoulder and reads the information/password you were trying to hide?

All this assuming you arnt in star trek

My Way

[Mignon]

The system uses a saturated CCD in a light-tight can as a chaotic source to produce the seed.

I use porn in a dimly-lit room to produce the seed. To each his own.

complex solution to a simple problem

[orb_fan]

High geek-factor aside, this seems way to complex for the simple task of generating random numbers.

Why not have a simple electronic circuit (it's been years since I've done any circuit design) that's balanced so that thermal noise produce ticks. Stick a USB interface on it and there you have it. A device you could carry in your pocket.

it's all about parallelism

[green pizza]

You need an SGI with at least two CPUs to take advantage of the superior LavaRnd abilities! Also, dump Netscape for Mozilla!

Your home PC LavaRnd setup may be able to generate a large random number faster than the SGI-based one... but the SGI LavaRnd has the architecture to generate many concurrent random numbers. It also has the ability to easily handle high definition random numbers without chugging!

=)

Talk about geeky

[wumpus188]

Lava lamp? Nah.. Real geeks use this

This is too cushy.

[finallyHasANickname]

1. Put flock on a transducer (microphone).
2. Play with it to discover what will turn out to be a normal distribution curve of frequency response.
3. Connect an A/D/RS-232 converter to it.
4. Blow at it, recording the white noise.
5. Employ compensation for the resonance, shuffling and compression at will--all in software.
6. Call it good.

The hedonic value should be high enough to leverage OSS on sourceforge more quickly than pr0n (even). Neglecting software development costs and software "mass production costs" (smirk), the project should cost $30 in quantities of one.

Hey, should we skip step one? (shrug) If we do, then I'm sorry I said this was too cushy. I lied. ;-)

BINGO

[smatt-man]

Why not use the bingo number tumbler for the seed?

Re:There's a statistician in the house!

[jovlinger]

As far as I know, a run of numbers has never won the lottery, so this is your chance. The run is more likely to come up, since one hasn't already, in all this time.

oh, wait...

Can someone please define a random number?

[einhverfr]

It seems to be that by our common definition of random, random numbers are in fact impossible. So I am wondering what the definition we are working with regarding random number is?

IMO, I think one stipulation of a true "random number" is that part of the seed has to be externally derived. I.e. in any closed system numbers cannot be truly random. This means doing things using as a seed, the previous random number hashed with the MD5SUM of the system time along with some external information which is unknowable by an attacker or other program. Mouse or keyboard activity, network traffic in some cases, maybe even an MD5SUM of the total range of I/O address ports...... Of course, that would have to be kernel level.

Re: Humans have trouble creating random numbers

[big-magic]

When I was in grad school (for mathematics), I took a course on probability. On the first day, the Prof gave an assigment for half the class to create a list of 100 random numbers using dice (actually one die). The other half of the class was to create the same list (numbers between 1 and 6), but without using any dice. The Prof then put all the pages in a pile, and was able to perfectly separate the pile based on which method was used to create the page with only a quick glance at each page.

We later learned that he was able to separate them by looking at runs of numbers. For a list of 100 uniformly distributed numbers (between 1 and 6), there is a very high probability (90% or greater) that there will be a consecutive run where the same number occurs 5 or 6 times in a row. But the people that manually created their list will almost never add such a run, because it doesn't seem "random" enough.

What is really "random" is a very hard question that has occupied many brilliant people over the last century.