More Generalized Clock-Controlled Alternating Step Generator

摘要

In this paper a new stream cipher generator, called More Generalized Clock-Controlled Alternating Step Generator is proposed for use in stream cipher applications. The design of the generator is simple, made up of three feedback shift registers which are connected such that one register (FSR A) controls the clocking of the other two registers (FSRs B and C). The generator generates a large family of output sequences using the same key (initial states and/or feedback functions). When the control register (PSR A) generates a de Bruijn sequence of period K = 2~κ and the other two registers (FSRs B and C) generate m-sequences of periods M = (2~m — 1) and N = (2~n — 1) respectively, then the output sequences have period P_z = 2~κ(2~m - l)(2~n - 1), linear complexity L bounded from below by (m + n)2~(κ-1) and from above by (m + n)2~κ. Furthermore, the distribution of short patterns in the output sequences occur equally likely and these sequences are secure against known correlation attacks.