# Random Number Generator (RNG)

Random Number Generators (RNG’s) generates sequences of numbers in a non-predictable manner. There are different types of random number generators available, such as hardware randon-number generators, or pseudo-random number generators. Pseudo-random number generators are in some sense random, but with the caveat that they can be reproduced given that the state/input of the RNG is known. RNG’s are used in a wide array of fields, such as cryptography, casino games (slot machines, digital roulette, etc) and lotteries (e.g. keno).

To generate pseudo-random numbers, a method such as taking the time and doing some mathematical operations can be used. However this has the downside that if someone on the other side manages to find out the operations used, can accurately determine the output given that the current time is known. Hence such a generator would not be sufficiently safe to use in for example casino games. To generate “true” randomness, sources such has atmospheric noise (electromagnetic energy from space) can be used. For companies such as online casinos the usage of “true” random number generators of extreme importance to avoid any players being able to determine the outcome of for example a digital roulette game. If such an exploit was to be found, this could have detrimental impact on the casinos revenue. This goes both ends, it would be possible for a casino to tamper with the RNG to increase it’s revenues. However laws to stop this from happening are usually enforced. For example slot machines in Las Vegas, Nevada, are heavily restricted. If a casino wants do to a change, they have to report this to the state, and the state also have inspectors which perform checks on the machines to ensure compliance, and that no players are being taken advantage of.

There are several services online which provide random number provided from measured physical processes. One such is the research group at Taiyuan University of technology which provides random numbers sampled from a so called “chaotic laser”.