Sample 09-F9 protest art, Free Speech Flag by John Marcotte

An illegal number is a number that represents information which is illegal to possess, utter, propagate, or otherwise transmit in some legal jurisdiction. Any piece of digital information is representable as a number; consequently, if communicating a specific set of information is illegal in some way, then the number may be illegal as well.

Background

A number may represent some type of

classified information Classified information is material that a government body deems to be sensitive information that must be protected. Access is restricted by law or regulation to particular groups of people with the necessary security clearance and need to know, ...

trade secret Trade secrets are a type of intellectual property that includes formulas, practices, processes, designs, instruments, patterns, or compilations of information that have inherent economic value because they are not generally known or readily asc ...

, legal to possess only by certain authorized persons. An AACS encryption key (09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0) that came to prominence in May 2007 is an example of a number claimed to be a secret, and whose publication or inappropriate possession is claimed to be illegal in the United States. It allegedly assists in the decryption of any

HD DVD HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to th ...

Blu-ray Disc The Blu-ray Disc (BD), often known simply as Blu-ray, is a Digital media, digital optical disc data storage format. It was invented and developed in 2005 and released on June 20, 2006 worldwide. It is designed to supersede the DVD format, and c ...

released before this date. The issuers of a series of cease-and-desist letters claim that the key itself is therefore a copyright circumvention device, and that publishing the key violates Title 1 of the US

Digital Millennium Copyright Act The Digital Millennium Copyright Act (DMCA) is a 1998 United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization (WIPO). It criminalizes production and dissemination of technology, devices, or s ...

. In part of the

DeCSS DeCSS is one of the first free computer programs capable of decrypting content on a commercially produced DVD video disc. Before the release of DeCSS, open source operating systems (such as Berkeley Software Distribution, BSD and Linux) could n ...

court order and in the AACS legal notices, the claimed protection for these numbers is based on their mere possession and the value or potential use of the numbers. This makes their status and legal issues surrounding their distribution quite distinct from that of

copyright infringement Copyright infringement (at times referred to as piracy) is the use of works protected by copyright without permission for a usage where such permission is required, thereby infringing certain exclusive rights granted to the copyright holder, s ...

Any image file or an executable program can be regarded as simply a very large

binary number A binary number is a number expressed in the base-2 numeral system or binary numeral system, a method of mathematical expression which uses only two symbols: typically "0" (zero) and "1" ( one). The base-2 numeral system is a positional notatio ...

. In certain jurisdictions, there are images that are illegal to possess, due to

obscenity An obscenity is any utterance or act that strongly offends the prevalent morality of the time. It is derived from the Latin ''obscēnus'', ''obscaenus'', "boding ill; disgusting; indecent", of uncertain etymology. Such loaded language can be use ...

or secrecy/classified status, so the corresponding numbers could be illegal. In 2011 Sony sued

George Hotz George Francis Hotz (born October 2, 1989), alias geohot, is an American security hacker, entrepreneur, and software engineer. He is known for developing iOS jailbreaks, reverse engineering the PlayStation 3, and for the subsequent lawsuit br ...

and members of fail0verflow for jailbreaking the

PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed by Sony Interactive Entertainment, Sony Computer Entertainment. The successor to the PlayStation 2, it is part of the PlayStation brand of consoles. It was first released on Novemb ...

. Part of the lawsuit complaint was that they had published PS3 keys. Sony also threatened to sue anyone who distributed the keys. Sony later accidentally retweeted an older

dongle A dongle is a small piece of computer hardware that connects to a port on another device to provide it with additional functionality, or enable a pass-through to such a device that adds functionality. In computing, the term was initially synonym ...

key through its fictional Kevin Butler character.

Flags and steganography

As a protest of the DeCSS case, many people created "

steganographic Steganography ( ) is the practice of representing information within another message or physical object, in such a manner that the presence of the information is not evident to human inspection. In computing/electronic contexts, a computer file, ...

" versions of the illegal information (i.e. hiding them in some form in flags etc.). Dave Touretzky of Carnegie Mellon University created a "Gallery of DeCSS descramblers". In the AACS encryption key controversy, a "

free speech Freedom of speech is a principle that supports the freedom of an individual or a community to articulate their opinions and ideas without fear of retaliation, censorship, or legal sanction. The rights, right to freedom of expression has been ...

flag" was created. Some illegal numbers are so short that a simple flag (shown in the image) could be created by using triples of

components Circuit Component may refer to: •Are devices that perform functions when they are connected in a circuit. In engineering, science, and technology Generic systems * System components, an entity with discrete structure, such as an assem ...

as describing red-green-blue colors. The argument is that if short numbers can be made illegal, then anything based on those numbers also becomes illegal, like simple patterns of colors, etc. In the '' Sony Computer Entertainment v. Hotz'' case, many bloggers (including one at

Yale Law School Yale Law School (Yale Law or YLS) is the law school of Yale University, a Private university, private research university in New Haven, Connecticut. It was established in 1824 and has been ranked as the best law school in the United States by ''U ...

) made a "new free speech flag" in homage to the AACS free speech flag. Most of these were based on the "dongle key" rather than the keys Hotz actually released. Several users of other websites posted similar flags.

Illegal primes

An illegal prime is an illegal number which is also

prime A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...

. One of the earliest illegal prime numbers was generated in March 2001 by Phil Carmody. Its

binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that t ...

representation corresponds to a compressed version of the C

source code In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the wo ...

of a

computer program A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer program ...

implementing the

decryption algorithm, which can be used by a computer to circumvent a DVD's

copy protection Copy protection, also known as content protection, copy prevention and copy restriction, describes measures to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on ...

. Protests against the indictment of DeCSS author

Jon Lech Johansen Jon Lech Johansen (born November 18, 1983 in Harstad, Norway), also known as DVD Jon, is a Norwegian programmer who has worked on reverse engineering data formats. He wrote the DeCSS software, which decodes the Content Scramble System used fo ...

and legislation prohibiting publication of DeCSS code took many forms. One of them was the representation of the illegal code in a form that had an ''intrinsically archivable'' quality. Since the bits making up a computer program also represent a number, the plan was for the number to have some special property that would make it archivable and publishable (one method was to print it on a T-shirt). The

primality A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...

of a number is a fundamental property of

number theory Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure mathematics devoted primarily to the study of the integers and arithmetic function, integer-valued functions. German mathematician Carl Friedrich Gauss (1777� ...

and is therefore not dependent on legal definitions of any particular jurisdiction. The large prime database of The

Prime Pages The PrimePages is a website about prime numbers maintained by Chris Caldwell at the University of Tennessee at Martin. The site maintains the list of the "5,000 largest known primes", selected smaller primes of special forms, and many "top twenty" ...

website records the top 20 primes of various special forms; one of them is proof of primality using the

elliptic curve primality proving In mathematics, elliptic curve primality testing techniques, or elliptic curve primality proving (ECPP), are among the quickest and most widely used methods in primality proving. It is an idea put forward by Shafi Goldwasser and Joe Kilian in 1986 ...

(ECPP)

algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...

. Thus, if the number were large enough and proved prime using ECPP, it would be published.

Other examples

There are other contexts in which smaller numbers have run afoul of laws or regulations, or drawn the attention of authorities. * In 2012, it was reported that the numbers 89, 6, and 4 each became banned search terms on search engines in China, because of the date (1989-06-04) of the

June Fourth Massacre June is the sixth month of the year in the Julian calendar, Julian and Gregorian calendars and is the second of four months to have a length of 30 days, and the third of five months to have a length of less than 31 days. June contains the summ ...

in Tiananmen Square. * Due to the association with gangs, in 2012 a school district in

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

banned the wearing of

jersey Jersey ( , ; nrf, Jèrri, label=Jèrriais ), officially the Bailiwick of Jersey (french: Bailliage de Jersey, links=no; Jèrriais: ), is an island country and self-governing Crown Dependencies, Crown Dependency near the coast of north-west F ...

s that bore the numbers 18, 14, or 13 (or the reverse, 81, 41, or 31). * In 2017, far-right Slovak politician

Marian Kotleba Marian Kotleba (; born 7 April 1977) is a Slovak politician and leader of the far-right, neo-Nazi

was criminally charged for donating 1,488 euros to a charity. The number is a reference to a white supremacist slogan and the

Nazi salute The Nazi salute, also known as the Hitler salute (german: link=no, Hitlergruß, , Hitler greeting, ; also called by the Nazi Party , 'German greeting', ), or the ''Sieg Heil'' salute, is a gesture that was used as a greeting in Nazi Germany. Th ...

References

External links