Scrambling by Reversible Conservative Bit Block Automata

Michael Schreiber

Wolfram Research

Abstract

Bit block automata return blocks of output bits for blocks of input bits. They are reversible if their rules include all possible input blocks among their output blocks. Those reversible systems conserve bit counts immediately if all their rule digits return output bits which are permutations of their input bits. Formulas for the numbers of these kinds of bit block automata are given. Scrambling of images is discussed as an example. Alternating conservation of bit counts is implemented for byte block automata as an example for models of reversible and non-reversible bit block systems which maintain zero total average energy.