Pseudorandom number generator

A Pseudorandom number generator ('PRNG) is "[a]n algorithm that produces a sequence of bits that are uniquely determined from an initial value called a seed. The output of the PRNG “appears” to be random, i.e., the output is statistically indistinguishable from random values. A cryptographic PRNG has the additional property that the output is unpredictable, given that the seed is not known." NIST, Special Publication 800-57.