# random number (RN)

Random numbers (RN) are numbers that occur purely by chance and are unpredictable and non-reproducible. They are statistically recurring numbers generated by a stochastic process.

Random numbers are obtained from noise or from the decay of radioactive elements. The random numbers derived from this process must meet certain criteria and tests. The random numbers must not be predictable or reproducible under any circumstances. The generation of random numbers in digital technology is correspondingly problematic, since the programs always work with certain initial and default values. Only programs that can generate numbers with the properties of random values are suitable for generation.

Random numbers are used in cryptography, especially in cryptographic algorithms generated via mathematical methods or derived from natural or physical events such as noise or radioactive decay processes. Random numbers derived from stochastic processes are referred to as "true" random numbers.

The security ofencryption methods is directly related to a possible reproducibility of the random number. Since the generation of true random numbers is not possible on a computer or software basis, pseudo-random generators are used in practice and work with pseudo-random numbers.