random number
{{Use mdy dates|date=July 2020}}
{{Use American English|date=July 2020}}
File:Two red dice 01.svg 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{{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}} 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.
{{cite magazine |magazine=Network Computing
|title=Privacy's Random Nature
|author=Robert Moscowitz |date=July 12, 1999}}{{cite magazine |magazine=Wired
|url=https://www.wired.com/1999/01/hardwiring-security
|title=Hardwiring Security |date=January 1999}} It has been described as "several oscillators combine their outputs and that odd waveform is sampled asynchronously."{{cite web
|url=http://www.ciphersbyritter.com/NEWS4/PENTRAND.HTM
|author=Terry Ritter |date=January 21, 1999
|title=The Pentium III RNG}} 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.{{cite web
|url=https://www.irisa.fr/caps/projects/hipsor/misc.php
|title=Unpredictable Randomness Definition |website=IRISA}}
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."
{{cite magazine |magazine=Sun Server
|title=Javatalk: Horseshoes, hand grenades and random numbers
|author=Jonathan Knudson |date=January 1998 |pages=16–17}}
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.
{{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}}A pre-compiled list of apartment numbers would be a violation thereof.{{examples|date=December 2022}}
Real world consequences
Flaws in randomness have real-world consequences.{{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}}{{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}}
A 99.8% randomness was shown by researchers to negatively affect an estimated 27,000 customers of a large service and that the problem was not limited to just that situation.{{clarify|date=December 2022}}