Luby and Rackoff showed a method for constructing a pseudo-random
permutation from a pseudo-random function. The method is based on
composing four (or three for weakened security) so called Feistel
permutations each of which requires the evaluation of a pseudo-random
function. We reduce somewhat the complexity ... more >>>

Most cryptographic primitives require randomness (for example, to generate their secret keys). Usually, one assumes that perfect randomness is available, but, conceivably, such primitives might be built under weaker, more realistic assumptions. This is known to be true for many authentication applications, when entropy alone is typically sufficient. In contrast, ... more >>>