[[File:Sample 09-F9 protest art, Free Speech Flag by John Marcotte.svg|thumb|right|225px|[[Free Speech flag]], from the [[AACS encryption key controversy|HD DVD AACS]] case]]

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 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.<ref name=carmody2>{{cite web |author=Phil Carmody |title=An Executable Prime Number? | url=http://asdf.org/~fatphil/maths/illegal.html |accessdate=2007-05-08 |quote=Maybe I was reading something between the lines that wasn't there, but if arbitrary programs could be expressed as primes, the immediate conclusion is that all programs, including ones some people wished didn't exist, can too. I.e. the so called 'circumvention devices' of which my previous prime exploit was an example. |archiveurl = http://web.archive.org/web/20070329055313/http://asdf.org/~fatphil/maths/illegal.html |archivedate = 2007-03-29}}</ref><ref name=reg20010319>{{cite news | author=Thomas C Greene |title=DVD descrambler encoded in ‘illegal’ prime number |work=[[The Register]] |date=2001-03-19 |url=http://www.theregister.co.uk/2001/03/19/dvd_descrambler_encoded_in_illegal/ |quote=The question, of course, is whether an interesting number is illegal merely because it can be used to encode a contraband program. |accessdate=2007-05-08}}</ref><ref>{{cite web|url=http://primes.utm.edu/glossary/page.php?sort=Illegal|title=The Prime Glossary: illegal prime|quote=The bottom line: If distributing code is illegal, and these numbers contain (or are) the code, doesn't that make these number [sic] illegal?|accessdate=2007-05-09}}</ref>

== Background ==

A number may represent some type of [[classified information]] or [[trade secret]], legal to possess only by certain authorized persons. An [[AACS encryption key controversy|AACS encryption key]] <!-- let us not post the number here, please, pending the Foundation's decision --> 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]] or [[Blu-ray Disc]] 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,<ref>{{cite web |title=AACS licensor complains of posted key |date= |url=http://www.chillingeffects.org/anticircumvention/notice.cgi?NoticeID=7180 |work=[[Chilling Effects (group)|Chilling Effects]] |quote=Illegal Offering of Processing Key to Circumvent AACS Copyright Protection [...] are thereby providing and offering to the public a technology, product, service, device, component, or part thereof that is primarily designed, produced, or marketed for the purpose of circumventing the technological protection measures afforded by AACS (hereafter, the "circumvention offering"). Doing so constitutes a violation of the anti-circumvention provisions of the Digital Millennium Copyright Act (the "DMCA") |accessdate=2007-05-08 }}</ref> and that publishing the key violates Title 1 of the US [[Digital Millennium Copyright Act]].

In part of the [[DeCSS]] court order<ref name=eff1>[https://w2.eff.org/IP/Video/MPAA_DVD_cases/?f=20000202_ny_memorandum_order.html Memorandum Order, in MPAA v. Reimerdes, Corley and Kazan (NY; Feb. 2, 2000)<!-- Bot generated title -->]</ref> 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 mere [[copyright infringement]].<ref name=eff1/>

Any image file or an executable program<ref>{{cite web|url=http://primes.utm.edu/curios/page.php?number_id=953|title=Prime Curios: 48565...29443 (1401-digits)|quote=What folks often forget is a program (any file actually) is a string of bits (binary digits)—so every program is a number.|accessdate=2007-05-09}}</ref> can be regarded as simply a very large [[binary number]]. In certain jurisdictions, there are images that are illegal to possess,<ref>{{cite web|url=http://www.statutelaw.gov.uk/content.aspx?LegType=All+Legislation&title=criminal+justice+act&Year=1988&searchEnacted=0&extentMatchOnly=0&confersPower=0&blanketAmendment=0&sortAlpha=0&TYPE=QS&PageNumber=1&NavFrom=0&activeTextDocId=2116852&parentActiveTextDocId=2116646&hideCommentary=0&showProsp=0&suppressWarning=0&showAllAttributes=1#attrib

|title=Criminal Justice Act 1988 + amendments|accessdate=2007-05-09}}</ref><ref>[http://en.wikipedia.org/w/index.php?title=Aniconism_in_Islam&oldid=106022656 Aniconism in Islam]</ref><ref>[http://en.wikipedia.org/w/index.php?title=Jyllands-Posten_Muhammad_cartoons_controversy&oldid=129022672#Aniconism Jyllands-Posten Muhammad cartoons controversy#Aniconism]</ref> due to [[obscenity]] or secrecy/classified status, so the corresponding numbers could be illegal.<ref name="carmody2"/><ref>{{cite book |title= Prime Numbers: The Most Mysterious Figures in Math |first= David |last= Wells |publisher= Wiley |year= 2011 |pages= 126–127 |section= Illegal prime |isbn= 9781118045718 }}</ref>

In 2011 Sony sued [[George Hotz]] and members of fail0verflow for [[privilege escalation|jailbreaking]] the [[PlayStation 3]].<ref>[http://www.engadget.com/2011/01/12/sony-follows-up-officially-sues-geohot-and-fail0verflow-over-ps/ Sony follows up, officially sues Geohot and fail0verflow over PS3 jailbreak]. Nilay Patel, Engadget (2011-01-12). Retrieved on 2011-02-16.</ref> Part of the lawsuit complaint was that they had published PS3 keys. Sony also threatened to sue anyone who distributed the keys.<ref name=ars11>{{cite web |url=http://arstechnica.com/gaming/news/2011/02/sony-lawyers-now-targeting-anyone-who-posts-playstation-3-hack.ars/ |title=Sony lawyers now targeting anyone who posts PlayStation 3 hack | date=February 8, 2011 |publisher=Arstechnica}}</ref> Sony later accidentally tweeted an older dongle key through its fictional [[Kevin Butler (character)|Kevin Butler]] character.<ref>{{cite web |url=http://www.engadget.com/2011/02/09/ps3-jailbreak-code-retweeted-by-sonys-kevin-butler-no-punchl/ |title=PS3 'jailbreak code' retweeted by Sony's Kevin Butler | date=February 9, 2011 |publisher=Engadget}}</ref>

== Flags and steganography ==

[[File:Free-speech-flag-ps3.svg|thumb|right|225px|The PlayStation 3 edition of the free speech flag.]]

As a protest of the DeCSS case, many people created "[[steganography|steganographic]]" versions of the illegal information. Dave Touretzky of Carnegie Mellon University created a "Gallery of DeCSS descramblers". In the [[AACS encryption key controversy]], a "[[free speech]] flag" was created. Some illegal numbers are so short that a simple flag (pictured to the right) could be created by using triples of [[numeral system|components]] as describing [[RGB color model#Numeric representations|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 America v. George Hotz|Sony Computer Entertainment v. Hotz]]'' case, many bloggers (including one at [[Yale Law School]]) 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.<ref>[http://www.yalelawtech.org/trusted-computing-drm/46-dc-ea-d3-17-fe-45-d8-09-23-eb-97-e4-95-64-10-d4-cd-b2-c2/ 46-dc-ea-d3-17-fe-45-d8-09-23-eb-97-e4-95-64-10-d4-cd-b2-c2] by Ben S, Yale Law Tech, 2011 March</ref> Several users of other websites posted similar flags.<ref>See [[:File:Free-speech-flag-ps3.svg]] description.</ref>

== Other examples ==

There are other contexts in which smaller numbers have run afoul of laws or regulations, or drawn the attention of authorities. In 2007, the [[Minister of the Interior (Belgium)|Belgian minister of the Interior]] wrote a letter to the Belgian Football Association asking them to forbid the wearing of football shirts displaying the numbers 88 and 18, but no player name, by fans in the stadiums, due to the connotation those numbers were deemed to have with [[Adolf Hitler]] in right-wing fan circles.<ref>{{cite web|title=Rugnummers 18 en 88 in opspraak |url=http://www.v-bal.nl/nieuws/bekijk.php?id=19721 |publisher=V-Bal.nl |language=Dutch |date=2007-01-23 |deadurl=unfit |archiveurl=https://web.archive.org/web/20070225075657/http://www.v-bal.nl/nieuws/bekijk.php?id=19721 |archivedate=February 25, 2007 }}</ref> A Swedish student's flat was visited by police in 2015 after the number "21" (that appeared on 2 balloons in the shape of the digits 2 and 1 marking her age) was mistaken by a passer-by for the letters "IS", which were suspected of signifying the [[Islamic State of Iraq and the Levant|Islamic State]] group.<ref>{{cite web|last1=Toppa|first1=Sabrina|title=Swedish Police Raid Apartment After Mistaking 21st Birthday Party Balloons for ISIS Initials|url=http://time.com/3721642/islamic-state-sweden-police-21-birthday-balloons-isis/|publisher=Time |accessdate=2015-03-09|date=2015-02-25}}</ref> Due to the association with gangs, a school district in [[Colorado]] banned the wearing of jerseys that bore the numbers 18, 14 or 13 (or the reverse, 81, 41 and 31).<ref>{{cite web|last1=Meyer|first1=Jeremy P.|title=Greeley school ban on gang numbers includes Peyton Manning's 18|url=http://www.denverpost.com/ci_21473182/greeley-school-ban-gang-numbers-includes-peyton-mannings|publisher=The Denver Post|accessdate=2015-03-09|date=2012-09-05}}</ref> 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 Incident]] in Tiananmen Square.<ref>{{cite web|last1=MacKinnon|first1=Mark|title=Banned in China on Tiananmen anniversary: 6, 4, 89 and ‘today’|url=http://www.theglobeandmail.com/news/world/worldview/banned-in-china-on-tiananmen-anniversary-6-4-89-and-today/article4228252/|publisher=The Globe and Mail|accessdate=2015-03-09|date=2012-06-04}}</ref>

== See also ==

* [[Illegal prime]]

* [[High-bandwidth Digital Content Protection#Master key release|HDCP master key release]]

* [[Texas Instruments signing key controversy]]

* [[Normal number]]

* [[Infinite monkey theorem]]

* [[The Library of Babel]]

* [[Prior art]]

* [[Streisand effect]]

== References ==

{{reflist}}

== External links ==

{{wiktionary}}

* {{cite journal |url= http://www.libraryjournal.com/article/CA6529387.html |title= Mediating between law and technology requires vigilance and education, not a technical solution |first1= Matthew |last1= Skala |first2= Brett |last2= Bonfield |first3= Mary Fran |last3= Torpey |journal= Library Journal |date= 2008-02-15 |archiveurl= https://web.archive.org/web/20130330020536/http://www.libraryjournal.com/article/CA6529387.html |archivedate= 2013-03-30 }}

* [http://ssrn.com/abstract=569103 "Trouble with Prime Numbers: DeCSS, DVD and the Protection of Proprietary Encryption Tools"]. ''Journal of Information, Law & Technology'', Vol. 3, 2002

* {{cite web|url=http://www.cs.cmu.edu/~dst/DeCSS/Gallery/Debate/index.htm|title=A Great Debate: Is Computer Code Protected Speech?|accessdate=2007-05-09}}

* {{cite web |url=http://www.opendemocracy.net/media/digging_in_4599.jsp |title=Digging in |date=2007-05-09 |author=[[Becky Hogge]] |publisher=[[openDemocracy]] |accessdate=2007-05-10}}

* [http://www.theregister.co.uk/2001/03/19/dvd_descrambler_encoded_in_illegal/ DVD descrambler encoded in ‘illegal’ prime number]

* [http://www.cs.cmu.edu/~dst/DeCSS/Gallery/Stego/index.html Steganography Wing of the Gallery of CSS Descramblers], Carnegie Mellon University, Dave Touretzky

* [http://www.newscientist.com/article/dn21597-us-judge-rules-that-you-cant-copyright-pi.html US judge rules that you can't copyright pi] by [[New Scientist]]

* [https://www.techdirt.com/articles/20130621/13594123566/american-bankers-association-claims-routing-numbers-are-copyrighted.shtml American Bankers' Association Claims Routing Numbers Are Copyrighted] by [[TechDirt]]

* [https://torrentfreak.com/orwell-estate-sends-copyright-takedown-over-the-number-1984-151027/ Orwell Estate Sends Copyright Takedown Over the Number 1984] by [[TorrentFreak]]

* [http://sprott.physics.wisc.edu/pickover/pimatrix.html We are in Digits of Pi and Live Forever] by [[Clifford A. Pickover]]

* {{cite web|last=Grime|first=James|title=Illegal Numbers|url=http://www.numberphile.com/videos/illegal_numbers.html|work=Numberphile|publisher=[[Brady Haran]]}}

[[Category:Cryptography law]]

[[Category:Numbers]]

[[Category:Trade secrets]]

[[Category:File sharing]]