Random number

{{Short description|Number generated by a random process}} {{Use mdy dates|date=July 2020}} {{Use American English|date=July 2020}}

[[File:Two red dice 01.svg|thumb|Dice are an example of a mechanical hardware random number generator. When a cubical die is rolled, a random number from 1 to 6 is obtained.|alt=]]

A '''random number''' is generated by a random (stochastic) process such as throwing dice. Individual numbers cannot be predicted, but the likely result of generating a large quantity of numbers can be predicted by specific mathematical series and statistics.

==Algorithms and implementations== Random numbers are frequently used in algorithms such as Knuth's 1964-developed algorithm<ref>{{cite journal |author=Richard Durstenfeld |title=Algorithm 235: Random permutation |doi=10.1145/364520.364540 |journal=Communications of the ACM |volume=7 |issue=7 |page=420 |date=July 1964}}</ref> for shuffling lists. (popularly known as ''the Knuth shuffle'' or ''the Fisher–Yates shuffle'', based on work they did in 1938).

In 1999, a new feature was added to the Pentium III: a hardware-based random number generator.<ref name=Random.NetwCom99> {{cite magazine |magazine=Network Computing |title=Privacy's Random Nature |author=Robert Moscowitz |date=July 12, 1999}}</ref><ref name=RandomPenIII.Wired99>{{cite magazine |magazine=Wired |url=https://www.wired.com/1999/01/hardwiring-security |title=Hardwiring Security |date=January 1999}}</ref> It has been described as "several oscillators combine their outputs and that odd waveform is sampled asynchronously."<ref>{{cite web |url=http://www.ciphersbyritter.com/NEWS4/PENTRAND.HTM |author=Terry Ritter |date=January 21, 1999 |title=The Pentium III RNG}}</ref> These numbers, however, were only 32 bit, at a time when export controls were on 56 bits and higher, so they were not state of the art.<ref>{{cite web |url=https://www.irisa.fr/caps/projects/hipsor/misc.php |title=Unpredictable Randomness Definition |website=IRISA}}</ref>

==Common understanding== In common understanding, "1 2 3 4 5" is not as random as "3 5 2 1 4" and certainly not as random as "47 88 1 32 41" but "we can't say authoritavely that the first sequence is not random ... it could have been generated by chance."<ref name=RandomArticle.SS1998> {{cite magazine |magazine=Sun Server |title=Javatalk: Horseshoes, hand grenades and random numbers |author=Jonathan Knudson |date=January 1998 |pages=16–17}}</ref>

When a police officer claims to have done a "random .. door-to-door" search, there is a certain expectation that members of a jury will have.<ref> {{cite news |newspaper=Los Angeles Times |url=https://www.latimes.com/archives/la-xpm-1995-04-16-mn-55166-story.html |title=NYPD Bad Cop's Illegal Search Mars Career |author=Tom Hays |date=April 16, 1995}}</ref><ref>A pre-compiled list of apartment numbers would be a violation thereof.</ref>{{examples|date=December 2022}}

==Real world consequences== Flaws in ''randomness'' have real-world consequences.<ref name=RandomArticle_Encr.NYT2012>{{cite news |newspaper=New York Times |url=https://www.nytimes.com/2012/02/15/technology/researchers-find-flaw-in-an-online-encryption-method.html |title=Flaw Found in an Online Encryption Method |author=John Markoff |date=February 14, 2012}}</ref><ref name=RandomArticle_Lott.NYT2012>{{cite news |newspaper=New York Times |url=https://www.nytimes.com/interactive/2018/05/03/magazine/money-issue-iowa-lottery-fraud-mystery.html |title=The man who cracked the lottery |author=Reid Forgrave |date=May 3, 2018}}</ref>

A 99.8% randomness was shown by researchers to negatively affect an estimated 27,000 customers of a large service<ref name=RandomArticle_Encr.NYT2012/> and that the problem was not limited to just that situation.{{clarify|date=December 2022}}

==References== {{Reflist}}

Category:Permutations