This video explaining this wikipedia article says that possessing a particular number can be illegal. Is this true?

From the article (internal links and formatting removed):

An illegal prime is a prime number that represents information whose possession or distribution is forbidden in some legal jurisdiction. One of the first illegal primes was found in 2001. When interpreted in a particular way, it describes a computer program that bypasses the digital rights management scheme used on DVDs. Distribution of such a program in the United States is illegal under the Digital Millennium Copyright Act. An illegal prime is a kind of illegal number.

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    Interesting question. I've heard this a lot, but I don't know any laws or court sentences to back up this claim.
    – A. Darwin
    Commented May 5, 2016 at 14:09
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    Any amount of information that can be communicated digitally can be encoded as a single number, provided you choose an encoding and are OK with the number being huge. So without qualifying what types of numbers and where they're coming from, "a number" can mean "any digital information".
    – Dan Getz
    Commented May 5, 2016 at 18:24
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    Note that a number itself does not mean anything. The number must be interpreted in a specific way to mean one thing or the other. I could devise an algorithm which takes a number as input and outputs a copyrighted book's content if the input was 5. Or, the other way around, if the number I published was binary ASCII representation of the same book that'd be much equivalent. The point is, if a "number" is legal or illegal depends on how it needs to be interpreted for a specific "illegal" result. If it's just an ASCII encoded text, that's common interpretation and thus may be illegal,
    – JimmyB
    Commented May 6, 2016 at 14:03
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    @JimmyB: if (input == 1) print(batman_vs_superman_mp4_data) else print("not illegal as far as I know"); ;-) Commented May 6, 2016 at 14:08
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    @SteveJessop Exactly. Does that program make 1 illegal? I don't think so because without a lot of additional information contained in the "decoding" algorithm the number itself is worthless.
    – JimmyB
    Commented May 6, 2016 at 14:17

4 Answers 4


Wikipedia explains this well enough: Particular numbers can be trade secrets, and their reproduction and dissemination may be particularly proscribed, e.g., by the U.S. DCMA.

As a coarse analogy: Your social security number is not "illegal." But if somebody entrusted with it shared it in violation of law or contract then their communication of the number in a context that allowed potential identity thieves to associate it with you would be illegal.

To answer follow-up questions in the comments: Sure, "mere possession" of a number can land one in jail for all sorts of crimes, just like "mere possession" of stolen property can. For example, if you possess a bank account number, credit card number, or PIN, and you "conspire, confederate, or combine with another" person who actually commits fraud or theft using that number, then you can be convicted of the same crime. This is so common that a search for "conspiracy to commit wire fraud" or "credit card fraud" provides ample reading.

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    Is there any court sentence or accepted scholar opinion on the topic? A quick online search shows at best some cease-and-desist letters, whose legality was considered dubious at the time.
    – A. Darwin
    Commented May 5, 2016 at 19:03
  • Is there any case in which mere possession of a number could be illegal? For example, having the digits of the number in decimal printed on a piece of paper. (And ignoring the fact that the number could be several millions of digits long.)
    – Era
    Commented May 5, 2016 at 19:18
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    This doesn't answer the question, which was about whether possession of a number could be illegal. Commented May 5, 2016 at 19:37
  • So what if person A's social security number is person B's credit card number? Commented May 7, 2016 at 17:06
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    @HagenvonEitzen - in such a case, should either person become aware of the alternate significance of the number, he should avoid using that fact to commit an act of fraud, or to conspire or combine with another who uses the number to commit fraud or theft. If the person is aware of the potential for fraudulent use of a number, the fact that it has some non-fraudulent personal significance or use does not provide a safe harbor against such criminal charges.
    – feetwet
    Commented May 7, 2016 at 18:16

A number is just information, and any information that an be encoded digitally has at least one corresponding number. So if there's information that can be encoded digitally that is illegal to possess, then there are numbers that are illegal to possess.

There are very few cases where mere intentional possession of information is illegal with no other elements at all, at least in most major countries. The most obvious example of such numbers would be digitally encoded images of illegal child pornography. Some countries have "born secret" laws that make it illegal to possess certain categories of information such as those relating to the design of nuclear weapons.

While there are few cases where mere intentional possession of a piece of information is a crime, there are all all kinds of "possession plus" offenses, where some additional act or element relating to the possession makes it illegal. In some jurisdictions, knowing possession of information obtained in specific illegal ways is illegal. Similarly, possessing information with intent to use it in a particular way or as part of a conspiracy to commit a crime can be illegal.

The "plus" part of many of these offenses can take place entirely in your head. For example, Florida Statute 817.568(2)(a) makes it illegal to possess certain identifying numbers if you intend to use them fraudulently. This is a law that explicitly makes it illegal to possess certain numbers if you have the wrong thoughts in your head about them.

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    Many laws define crimes in terms of intent. A jury isn't expected to be telepathic, however, but rather to examine a person's actions and the circumstances around them and decide whether it is plausible that the actions may have been taken for any purpose other than the forbidden one. Laws which criminalize actions based on intent are often far more just than those which attempt to define criminality based purely on legally-defined actions, since the latter will often either allow people to systematically victimize others using loopholes, or ensnare people who meant no harm.
    – supercat
    Commented May 6, 2016 at 5:09
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    For example, if you have ten thousand secretly-obtained credit card numbers on your computer, you might say, "Nothing illegal about having ten thousand sixteen-digit numbers on my computer!" but obviously any jury can guess that you were not planning to do something nice with thousands of numbers that happen to correspond to active credit card numbers. (Nice answer.)
    – apsillers
    Commented May 6, 2016 at 16:59

Can numbers be illegal?

This video explaining this wikipedia article says that possessing a particular number can be illegal. Is this true?

If your question, as given in the topic, is interpreted literally, without the context from that video and article and without any possible other interpretations, then the answer is clearly and absolutely "no".

It is not possible that "possessing" a particular number can be illegal, in any form or fashion.

All cases mentioned in the other answers, as well as in your text and video, are not the possession of a "number", but of some information "xyz" which happens to contain a number as part of it.

Let me give you a simple example: say I write a diploma thesis and count the number of cars that drive by my home during a day. I end up at 322884 (it's a busy street). It just so happens that the PIN for launching the nuclear arsenal of my country also happens to be 322884. If it were illegal to possess that number, I would go to jail.

Sure, I do "possess" that number. It is clearly written on my hard drive, I have printed it on my thesis, I have even publicised it. So if the NSA does a full-out scan of all my property, they would easily find it. I did not possess the information that it is the nuke-PIN, though. So I will most certainly not go to jail for it.

TL;DR: yes, it can be illegal to possess a certain information. No, it cannot be illegal to possess a certain number (without connotation).

  • This is a good argument, and AFAIK it comports with the law. But it begs two questions, which I enumerate here.
    – feetwet
    Commented May 6, 2016 at 14:28
  • I would suggest the following solution. Write an FLOSS tool that checks yous systems using pattern matching for illegal numbers and remove them. There shall be a list with comments to keep track of everything. e.g. 1234 #used to unlock dvd, 4312 #us president email password, 3254:trump credit card number; sounds like a plan? Commented May 7, 2016 at 20:28
  • @akostadinov, not sure what you're trying to say. Note that my answer uses reductio ad absurdum to bring my point across, it does not pose an additional problem that needs a solution...
    – AnoE
    Commented May 8, 2016 at 8:07
  • I'm just proposing a solution to keep users' drives clean from the illegal numbers ;) I'm certain NSA will be very happy with it. / or I'm using same approach to show one cannot protect oneself from that. Commented May 9, 2016 at 12:47

If you represent an image as a number where each pixel is represented by a number of bits you can represent an image as a single number. This is commonly the form images are stored on disk.

As there are images that are illegal to posess (in most countries I suspect) then the number that represents an image depicting child pornography could be considered illegal.

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