A random number generator is a computational or physical device designed to generate a sequence of numbers that does not have any easily discernable pattern, so that the sequence can be treated as being random. Random number generators have existed since ancient times, in the form of dice and coin flipping, the shuffling of playing cards, the use of yarrow stalks in the I Ching, and many other methods.
Wikipedia:RGN, DeWikipedia:Zufallszahlengenerator
Most computer programming languages include functions that purport to be random number generators. They are usually designed to provide a floating point number uniformly distributed between 0 and 1.
Such functions are deterministic, and therefore not truly random; furthermore, they often have poor statistical properties and sometimes will repeat patterns tens of thousands of trials. They are sometimes initialized using the computer's real time clock, which may provide enough randomness for purposes such as game play, but they should never be used for cryptographic purposes.
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Random numbers available over the internet and from parties not specifically known to and trusted by the user should not be used cryptographically.
- Random.org - 73820 million random bits served since October 1998 (random numbers generated from atmospheric noise from a radio, generate random bitmaps, flip virtual coins etc.)
- HotBits: Genuine Random Numbers (random numbers generated from radioactive decays)
- RandomNumbers.info (random numbers generated by exploiting elementary quantum optics process)
- KenoRND (random numbers generated from results of live keno at real casinos)
- www.true-random.com (random numbers generated from digital noise and based on the central limit theorem)
Related: PRNG