RANDOM.ORG is a true random number service that generates randomness via atmospheric noise. This page contains frequently asked questions (and answers!) related to the service.
Section 1: Questions about the Service and Software
Section 2: Questions about the Numbers
Section 3: Questions about How to Use the Service
Section 4: Questions about the Premium Generator and the Quota System
Section 5: Questions about the Third-Party Draw Service
Section 6: Questions about Documentation and Media Coverage
Section 7: Questions about Parapsychology and Global Consciousness
Excellent question! I suggest you either register for a RANDOM.ORG account or make a donation to Concern. In case you don't know them, Concern is a charity that helps poor people in the third world achieve self-sustainable improvements in their lifestyles as described in Concern's mission statement. I recommend them because I agree with their mission statement and because they are pretty efficient compared to many of the other charities I have looked at. If you decide to make a donation to Concern because of RANDOM.ORG, it'd be great if you could tell me about it, since Concern don't automatically do that. (I suppose they have better things to do.) And it makes me so happy!
Not currently, no. Maybe I'll make it available as open source some day.
No. It's not just the software you'd need, but also three radios (or one, at any rate), which must be carefully adjusted to pick up atmospheric noise at the right volume. It's not completely trivial to set up.
RANDOM.ORG uses radio receivers to pick up atmospheric noise, which is then used to generate random numbers. The radios are tuned between stations. A possible attack on the generator is therefore to broadcast on the frequencies that the RANDOM.ORG radios use in order to affect the generator. However, radio frequency attacks of this type would be difficult for a variety of reasons. First, the frequencies that the radios use are not published, so an attacker would have to broadcast across all frequencies of all bands used for FM and AM broadcasting. Second, this is not an attack that can be launched from anywhere in the world, only reasonably close to the generator, meaning an attacker would have to be in Dublin. Third, if an attacker actually did succeed at broadcasting highly regular signals (e.g., perfect sine waves) at exactly the right frequencies, then the RANDOM.ORG real-time statistics would pick up the drop in quality very rapidly. In particular, I would expect the Source Purity and Information Entropy tests to start failing dramatically, which would alert me to the attack.
Probably, depending on your value for X. I have run the service since 1998 with no real interruptions, and it is more popular than ever. I am not planning to sell it or shut it down, and I do have a succession plan in the works.
Yes. Perhaps you need more numbers than it's possible to get via the web forms, or perhaps you need them in a format that isn't supported. In those cases, I can set up a custom job for you to supply the numbers. I also act as an independent observer for drawings and competitions via the Third-Party Draw Service.
There is typically a charge associated with custom jobs. You can email me for further details.
RANDOM.ORG will send email to you when you register for a Premium Account or if you have forgotten your password. It can also email you if you use the Premium Generator or the Third-Party Draw Service. If you have problems receiving any of these emails, please check your spam filter configuration. It should be set to accept emails from notifications@random.org as well as Mads.Haahr@cs.tcd.ie. If you are still experiencing problems, let me know.
Oddly enough, it is theoretically impossible to prove that a random number generator is really random. Rather, you analyse an increasing amount of numbers produced by a given generator, and depending on the results, your confidence in the generator increases (or decreases, as the case may be). This is explained in more detail on my Statistical Analysis page, which also contains two studies of the numbers generated by RANDOM.ORG, both of which concluded that the numbers are sound. In addition, the continually updated Real-Time Statistics page gives you an indication of the quality of the numbers produced over time.
For any form that allows the numbers to be formatted in multiple columns, the numbers are generated on a per-row basis, not per-column. Hence, if you want to read them in the order they were generated, you should read them across. Since they're random numbers, it doesn't really matter whether you do it one way or the other, but you should pick one of the two ways and read that way consistently.
Yes, since April 2007 you can access the server via https://www.random.org/
I should probably note that while fetching the numbers via secure HTTP would protect them from being observed while in transit, anyone genuinely concerned with security should not trust anyone else (including RANDOM.ORG) to generate their cryptographic keys.
Currently, there isn't a lot you can do, except email me and tell me this is a problem for you (see also question 1.6). For some of the forms, the limit is there because it requires time to generate random numbers and the server is pretty busy. For other forms, the restriction is related to the available memory in my server. I'm thinking about making a premium service that will allow bigger intervals for a small fee. If you think this is a great idea, let me know, and I may do it sooner than I will otherwise.
If you can do your own programming, you may be able to use the pregenerated files. They contain large amounts of pregenerated raw random data that you can download and use as you please. However, you will probably need to process the files for your specific purpose; hence the need for programming skills.
Some of the forms allow you to choose between three different types of randomization. If you're not sure what to choose, you almost certainly want to ‘generate your own personal randomization right now,’ which is the first (and default) option. In this mode, your numbers (or strings or whatever) will be generated based on true randomness created especially for you and which will be discarded immediately after it has been used. There is no way to predict what these numbers will be, and there is no way to recreate the same numbers later. This is the standard way of using a true random number generator.
The other two modes allow you to select a pregenerated randomization, which means that your numbers or strings will be based on randomess generated by RANDOM.ORG some time in the past. These modes allows you to replay a given sequence of numbers at a later stage, and allows multiple parties in different locations to get the same numbers in a predictable fashion. These modes effectively turn RANDOM.ORG into a pseudo-random number generator.
todo: more here
Currently, the generators support only the discrete uniform distribution. The only exception is the Gaussian Generator, which supports the Gaussian distribution (also known as the normal distribution). No other distributions are currently supported. If you would like to see other distributions, email me the details and I may choose to include them in the future.
Sometimes people email me to say that they feel the Die Roller produces too many repeated numbers (e.g., that it is hard to roll five dice without getting two or more identical rolls) or that the Coin Flipper produces too many heads or tails when used with several coins. Such concerns are great illustrations of how difficult it is for humans to deal with randomness. Our brains are so good at finding patterns that we tend to see them even where they aren't. (This is why statistical tests are useful and why the Real-Time Statistics for RANDOM.ORG's numbers are published online.)
So let's do the math for an example where we're rolling five dice. Intuitively, you may expect that the five rolls should come up different a lot of the time. (At least this is what people often mention in emails.) So what's the chance of all the five rolls being different? The first die is trivial. Any of the six possible values is fine (none will result in duplicates), giving a probability of 6⁄6 = 1. After you've rolled the first die, the chance of the second coming up different from the first is 5⁄6, because there is now one less value you haven't seen before. The third is 4⁄6, and so on. Hence the total probability of all your five rolls turning out different is:
6⁄6 × 5⁄6 × 4⁄6 × 3⁄6 × 2⁄6 ≈ 9.26%
Hence, if you roll five dice repeatedly, you should expect over 90% of the rolls to contain duplicates. If you roll six dice, you can multiply the value above by a further 1⁄6 and you'll get approximately 1.54%. Hence, if you roll six dice repeatedly, you can expect to get six different values only about once in every 65 rolls. The following table shows the probabilities:
| Number of Dice Rolled | Chance of Duplicates |
|---|---|
| 1 | 0% |
| 2 | ~16.7% |
| 3 | ~44.4% |
| 4 | ~72.2% |
| 5 | ~90.7% |
| 6 | ~98.5% |
For a great little introduction to calculating probabilities, check out John Walker's Introduction to Probability and Statistics.
Many people are using RANDOM.ORG for this purpose. Since March 2007, there is the Third-Party Draw Service, which is especially intended for holding drawings and which will keep records of the outcome. The records serve as evidence that the drawing was conducted fairly, in case someone should question it later on. See the Guide to Random Drawings and section 5 of this FAQ for further details.
If you have no budget but a group of entrants who trust you, then you can use the Sequence Generator. In this case, RANDOM.ORG will not store a record of the result, so your entrants cannot verify the result. Let us assume you have sold or given out sequentially numbered lottery tickets, e.g., numbered 1-250 (if not, see the next question). Then do the following:
People who ask this question often want to use the service for picking people for drug screening or as winners for lotteries or drawings. Since January 2007, there is the List Randomizer, which will probably do what you want. However, I will ask you not to enter any confidential information (e.g., the names of your employees or their social security numbers) into the form. I don't log the data that people enter into this form, but since I'm not currently using encryption to secure the communication between your browser and the server (see question 2.3), someone else could observe the names or numbers you enter into the form while they're in transit.
If you don't want to use the List Randomizer (for example for privacy reasons), it's also pretty easy to do it using the Sequence Generator and a spreadsheet. Here's how:
You can use this technique with any type of data, not only names, but also employee numbers, etc. It will work with up to 10,000 entries, which is the maximum sequence length that the Sequence Generator allows.
Not directly, but you can use David Goodrich's draw straws application, which uses numbers from RANDOM.ORG.
People who ask this question are usually using the Lottery Quick Pick or the Keno Quick Pick. The short answer is that RANDOM.ORG won't give you a better chance of getting a winning combination, but if you do happen to win, you are likely to get slightly better winnings than if you weren't using a quick picker.
Now for the long answer. There are really two different parts to winning a great lottery prize. First, there is the chance of getting a winning combination on your ticket, and then there is the value that this ticket will have. If many others played the same combination as you, you will have to share the pot with them, which will result in a smaller payout for you. (Sharing is great in many aspects of life, but in lotteries, these are the facts.) So in answering this question, let's deal with (1) getting a winning combination and (2) estimating the size of the prize one at a time.
With regard to getting a winning combination, a good few of the people who email me seem to believe that it is possible to predict the outcome of lotteries (or at least to improve your odds) by using a particular strategy. These strategies are typically based on analysis of past winning numbers and are often implemented as ‘lottery winning software.’
Unfortunately, I don't believe there is any strategy or software that will help you improve your odds. Such strategies are based on the idea that numbers or patterns that have come up in the past are less likely to appear in the future. However, for any properly operated lottery, the numbers are picked in a fashion that is statistically independent, which means that a number or a combination that has been picked in the past isn't less likely to occur next week. A simple way to think about it is that the machine that picks the winning numbers has no memory of what happened in previous drawings. The only way to improve your odds is to buy more tickets, but this gets very expensive very quickly. So, like any other other properly constructed quick pick, RANDOM.ORG's Lottery Quick Pick will not give you any special advantages for obtaining a winning ticket.
However, if you play the lottery on a regular basis, using a quick picker is likely to give you a small advantage over the players who don't use one. For all properly operated lotteries, all the possible combinations are equally likely to be drawn as the winning one. In reality, however, people often behave intuitively rather than rationally, so all the possible numbers are not equally popular with the players. Many people play their own birthdays or those of family members, which means that 1-31 and especially 1-12 (which of course can be a day as well as a month) are overplayed compared to other numbers. In addition, most people when filling in coupons by hand opt for combinations that visually ‘look’ random on the coupon, leading them to avoid straight lines, perfect squares and other combinations that, when the boxes are checked on the coupon, result in geometric shapes that seem ‘too regular’ to the human eye, but in reality have exactly the same chance of becoming the winning combination as any other combination. How often have you ever played all the corner numbers on a lottery coupon?
By playing unpopular numbers or combinations, you can increase your expected payout, because you would (on average) share the pot with fewer other winners. You aren't any more likely to obtain a winning ticket, but in case you do, you're likely to win a bigger share. However, it should be noted that lottery odds are still not good, and that most lotteries give much poorer payouts (50% of revenues is not atypical) than many other types of gambling.
Thanks to Dag Oystein Johansen for some of the thoughts on lotteries!
People who ask this question has often read A Random Walk Down Wall Street by Princeton economist Burton Malkiel who argues that share prices exhibit randomness in the form of random walk behaviour.
I have not personally experimented with playing the stock market using numbers from RANDOM.ORG, and as as disclaimer I should say that I don't have a very deep understanding of market behaviour. However, if Prof. Malkiel's thesis is correct, then I fail to see how RANDOM.ORG could be helpful in predicting stock movements. Certainly, true random numbers can be used to simulate a fictive stock market, but being based on randomness, the simulation will yield different results every time you run it, and each result is as likely to be as useful a predictor as the next one.
One use of RANDOM.ORG that people have mentioned in relation to the stock market is if you need to make trades that are independent of market trends. As noted in my introduction to randomness, it is surprisingly difficult for humans to behave randomly, so if you need make trades that are certain not to be affected by your (conscious or unconscious) knowledge of the market, then RANDOM.ORG may be helpful.
Some people who ask this question believe that the stock market is affected by (and/or affects) a type of human global consciousness. I have not seen any evidence to support this type of theory, but if it interests you see section 6 of this FAQ.
The easiest way to do this is to use the List Randomizer as follows:
This will work with up to 10,000 items, which is the maximum number of items that the List Randomizer supports. If you have more items, you will need a subscription to the Premium Generator and should use the procedure described in question 3.7.
In this case, you will need a subscription to the Premium Generator. Then use the following procedure:
This procedure will allow you to pick up to 10,000 items from a list of up to 1,000,000,000. (Actually, the list can be up to 2,000,000,001 items long but then you need to assign negative numbers to some of them, which can be a bit messy.)
Generating true random numbers takes time. The RANDOM.ORG setup uses an array of radios that pick up atmospheric noise. Each radio generates approximately 3,000 bits per second. The random bits produced by the radios are used as the raw material for all the different generators you see on RANDOM.ORG. Each time you use one of the generators, you spend some bits. By enforcing a limit on the number of bits you can use per day, the quota system prevents any one person from hogging all the numbers. (Believe me, this was a big problem before I implemented the quota system.)
A bit is a value that can be either 0 or 1. On RANDOM.ORG, a bit is the basic unit of randomness. The generator essentially generates one long string of one 0s and 1s. Every time you request some numbers, flip some coins or use one of the other services, you use some of these bits. Exactly how many depends on which of the services you are using. For example, flipping a single coin with the Coin Flipper uses exactly one bit. If the bit is 0, your coin comes up reverse (typically tails) and if it's 1, the coin comes up obverse (typically heads).
The other RANDOM.ORG services (such as the Integer Generator and the String Generator) require different amounts of bits, depending on how many numbers or strings you request. You can always check your quota to see how many bits you have left of your allowance. (See question 4.1 about why there is an allowance in the first place.)
If you need to generate many numbers or strings, it is useful to know how many random bits it is going to require. The number of bits needed affects how fast you will be able to generate the numbers (or strings) if you are using the free daily allowance of bits. If you want to purchase an extra allowance, the number of bits required helps you determine how large an extra allowance you need.
At the moment, it is a little tricky to calculate the exact number of bits required for generating numbers and strings, because the number of bits varies with the size of the interval for numbers and for the length of strings, etc. I am planning to extend the various generators such that they will tell you exactly how many bits were used each time you use them, but I haven't had the time to do this yet.
In the meantime, the best way is simply try it out by first checking your quota, then requesting a small number of numbers or strings with the parameters you need and then checking your quota again immediately afterwards. The difference in your quota level before and after will tell you how many bits were required for your request. You can then use that number of bits to calculate the total number of bits you need in order to generate all the numbers or strings that you want.
The Third-Party Draw Service is for professional operators of raffles, sweepstakes, promotional giveaways and other lottery type services. In a similar fashion to a certified official, RANDOM.ORG acts as an unbiased third party who conducts the drawings in a manner that is guaranteed to be fair and truly random.
Drawings are priced according to the number of entrants in them. The Price Calculator will tell you exactly how much. A drawing can have multiple winners (1st, 2nd, etc.), which does not affect the cost.
To use the service, you must create a RANDOM.ORG Premium Account with at least $4.95 worth of prepaid credit. The prepaid credit is used to pay for your drawings. There is no maintenance fee for use of the Third-Party Draw Service, only the cost of the drawings.
It is also possible to arrange a flat-fee per-month subscription for unlimited use of the Third-Party Draw Service. This model is favoured by PR and Media companies that hold many and/or large drawings. For details, please inquire.
The record of a given drawing persists for at least five years from the time at which the drawing was completed.
The Third-Party Draw Service currently supports up to 2,000,000 entrants and 100 winners in a single drawing, but more can be accommodated on request.
RANDOM.ORG will never use the email addresses that you upload for anything else than allowing people to verify their participation in your drawings. We respect your entrants' privacy and disapprove of spam as much as you do.
When you use entrants' email addresses to hold drawings, please make sure your drawings are entrant-accessible or private. This ensures the email addresses will not appear on the records of your drawings.
No.
No. It is not possible to modify the record of a completed drawing.
Not currently. I don't really consider it research as such, more like a useful piece of engineering. See question 6.3 for how to cite RANDOM.ORG.
Yes, see the Media and Citations page for details. If you publish a peer-reviewed publication that references RANDOM.ORG, it would be great if you could drop me an email.
You are certainly welcome to do so, and you don't need my express permission to do either. Since I haven't yet documented RANDOM.ORG in a scientific publication, I suggest you cite the web site.
Probably not. The numbers generated by RANDOM.ORG are buffered, which means that they are actually generated before you request them. I understand that this precludes their use in those parapsychological experiments that attempt to measure whether it is possible for individuals to affect otherwise random events.
People who ask this question have usually read about the Global Consciousness (GC) Project. The GC people collect data generated by true random number generators and analyse it for anomalities occuring at the same time as events affecting large groups of people, such as major earthquakes, Lady Diana's funeral or the 9/11 attacks. Seemingly, the GC results show strange anomalies in data generated around the time of the attacks. This has lead people to ask me if I have noticed any change in the numbers generated by RANDOM.ORG on that day.
The short answer to this question is really no. However, I should qualify to say I don't think it's meaningful to compare, and that a comparison doesn't say anything (either way) about the GC results, simply because the software I'm using is not intended to be used for the type of experiment the GC people are doing. First, I don't keep the numbers around for later; they're discarded as soon as they've been served to clients. Second, the generator doesn't produce a constant stream of numbers (like I presume the GC project's generators do) but works in a kind of start-and-stop mode, depending on whether the numbers are needed or not. For this reason, there are periods of time (at least on most days) where the generator is not producing numbers.
In short, no. Like for 9/11 (see question 7.2), I haven't analysed the logs thoroughly with this in mind, and the generator isn't at all geared towards this type of experiment.
Yes. No. Maybe. Well, I hope not, because if the universe is deterministic, then all this randomness business is really a bit pointless. Hard determinism also seems to preclude the idea of free will, which is a somewhat unsettling idea. Wikipedia has a good article on the subject of determinism and there is also my own essay about randomness.
© 1998-2009 Mads Haahr