In [[mathematics]] and [[computer science]], a '''balanced booleanBoolean function''' is a [[booleanBoolean function]] whose output yields as many '''0'''s as '''1'''s over its [[Domain of a function|input set]]. This means that for a uniformly random input string of bits, the probability of getting a '''1''' is 1/2.
Examples of balanced booleanBoolean functions are the function that copies the first bit of its input to the output,
and the function that produces the [[exclusive or]] of the input bits.
== Usage ==
Balanced booleanBoolean functions are primarily used in [[cryptography]]. If a function is not balanced, it will have a [[statistical bias]], making it subject to [[cryptanalysis]] such as the [[correlation attack]].
