v2.0 beta
True Random Number Service

Frequently Asked Questions (FAQ)

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 Services and the Quota System

Section 5: Questions about Documentation and Media Coverage

Section 6: Questions about Parapsychology and Global Consciousness

Section 1: Questions about the Service and Software

Q1.1: I use RANDOM.ORG a lot. How can I show my appreciation?

Excellent question! I suggest you either make a donation to Concern (best option) or send me a gift from my Amazon.com Wishlist (also appreciated). 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!

Q1.2: Is the source code for the generator available?

Not currently, no. Maybe I'll make it available as open source some day.

Q1.3: Can I download the generator software and run it on my own computer?

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.

Q1.4: Could someone affect the numbers by broadcasting a radio signal?

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 the entire FM band. 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 a very regular signal (e.g., a perfect sine wave) at the right frequency, 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.

Q1.5: Will RANDOM.ORG be around in X years?

Probably, depending on your value for X. I have run the service since 1998 with very few interruptions. I'm not planning to sell it or shut it down, at least not at the moment.

Q1.6: Does RANDOM.ORG perform custom jobs that require randomness?

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 draws and competitions via the Third-Party Draw service.

There is typically a charge associated with custom jobs. You can email me for further details.

Section 2: Questions about the Numbers

Q2.1: How can you be sure the numbers are really random?

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.

Q2.2: Should the tables of generated numbers be read across or down?

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.

Q2.3: Are the numbers available in a secure fashion?

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 me to generate their cryptographic keys.

Q2.4: What if I need more numbers than is allowed by the forms?

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.

Q2.5: What's the story with the different randomizations mentioned on some of the forms?

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

Q2.6: Which probability distributions are supported?

Currently, the only distribution supported is the discrete uniform distribution. If you would like to see other distributions, email me the details and I may choose to include them in the future.

Section 3: Questions about How to Use the Service

Q3.1: How do I pick winners for a lottery or draw?

Lots of people are using RANDOM.ORG for this purpose. Since March 2007, there is the Third-Party Draw Service, which is especially intended for this purpose and which will keep records of the outcome of your draw, so you have evidence that the draw was conducted fairly, in case someone should question it later on. Using the Third-Party Draw Service also supports a draw of any size. You need a premium account to use the Third-Party Draw Service.

If your draw has less than 10,000 participants and you don't need RANDOM.ORG to store a permanent record of the result, then you can use the Sequence Generator, which doesn't require a premium account. I'm assuming 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:

  1. Go to the Sequence Generator.
  2. Type in 1 as your smallest value and the number of tickets sold as your largest, then hit the submit button.
  3. On the resulting list, the first number is the number of the winning ticket. If you have a second prize in your lottery, the second number on the list is the number of the second winning ticket, and so on. Discard any unused numbers.

Q3.2: How do I randomize a list of people's names?

People who ask this question often want to use the service for picking people for drug screening or as winners for lotteries or draws. 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 email addresses) 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 email addresses 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:

  1. Format your names in one column in a spreadsheet. Let's call it column A.
  2. Go to the Sequence Generator.
  3. Type in 1 as your smallest value and the number of rows in your spreadsheet as your largest, then hit the submit button.
  4. Copy and paste the list produced into a separate column in your spreadsheet. Let's call it column B. The two columns contain the same number of rows and must match up.
  5. Sort the rows in your spreadsheet in ascending order using column B.
  6. Column A now contains your randomized names.

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.

Q3.3: Can I use RANDOM.ORG to draw straws?

Not directly, but you can use David Goodrich's draw straws application, which uses numbers from RANDOM.ORG.

Q3.4: Can RANDOM.ORG help me win the lottery?

Probably not. People who ask this question are usually using the Lottery Quick Pick form, and a good few 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 draws. The only way to improve your odds is to buy more tickets, but this gets very expensive very quickly.

So, while RANDOM.ORG's Lottery Quick Pick is great for picking combinations of numbers, it doesn't give you any special advantages. It's exactly as good as any other properly constructed quick pick.

Section 4: Questions about the Premium Services and the Quota System

Q4.1: Why is there a limit to the amount of randomness I can use per day?

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.)

Q4.2: What exactly constitutes a bit and how many bits do I need?

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 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.

Q4.3: What type of premium account do I need?

A Premium Account gives you access to the most advanced functionality on RANDOM.ORG. These accounts come in two flavours: Personal and Corporate. If you intend to use the RANDOM.ORG premium services for personal use, you should choose a Personal Account. If you are taking out a subscription for a corporation or an institution, please choose a Corporate Account. The functionality for the two types of accounts is currently identical, but some of the future services will be accessible only to Corporate Account holders. By taking out a subscription, you help RANDOM.ORG become a more useful service to businesses and individuals on the Internet.

Section 5: Questions about Documentation and Media Coverage

Q5.1: Are there any scientific publications that document RANDOM.ORG?

Not currently. I don't really consider it research as such, more like a useful piece of engineering. If you want to cite RANDOM.ORG, I currently recommend you cite the web site.

Q5.2: Has the service been cited in peer-reviewed publications?

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.

Section 6: Questions about Parapsychology and Global Consciousness

Q6.1: Are the numbers suitable for parapsychological experiments?

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.

Q6.2: Were there anomalies in the numbers on 11 September 2001?

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.

Q6.3: Were there anomalies in the numbers during the Asian tsunamis on 26 December 2004?

In short, no. Like for 9/11 (see question 6.2), I haven't analysed the logs thoroughly with this in mind, and the generator isn't at all geared towards this type of experiment.

Q6.4: Is the universe deterministic?

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.

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