1. A device used to invert the sense of pseudorandomly selected bits of a bit stream to avoid long sequences of bits of the same sense.
Note: The same selection pattern must be used on the receive terminal in order to restore the original bit stream.
2. [An] analog or digital source of unpredictable, unbiased, and usually independent bits.
Note: Randomizers can be used for several different functions, including key generation or to provide a starting state for a key generator.
Source: from Federal Standard 1037C and from MIL-STD-188 and from the National Information Systems Security Glossary