abstract:A randomness extractor, often simply called "an extractor," is a certain kind of pseudorandom generator which, when applied to a sufficient quantity of output from a (possibly) weakly random, entropy source (such as radioactive decay, or thermal noise), generates a highly random output that is independent and uniformly distributed. The only restrictions on possible sources is that they are nondeterministic to the extent that there is no way the source can be fully controlled, calculated or predicted and that a lower bound on their entropy rate can be established.