Dynamic LFSRs as an alternative to LFSRs in extended fields - A comparative study

Abstract

Linear feedback shift registers (LFSRs) with dynamic feedback (DLFSRs) and LFSRs defined over extended fields i.e., over GF(2n), constitute building blocks of many pseudorandom sequence generators used in stream ciphers. In this work, the advantages and disadvantages of using DLSFR instead of LFSR in GF(2n) are analyzed. The work is based on the possibility of obtaining a DLFSR in GF(2) equivalent to an LFSR in GF(2n), given that both structures present equivalent binary models formed by interleaved sequences. Likewise, the possibility of using DLFSR on binary vectors is proposed in order to take advantage of the word lengths of current processors.