Using Linear Difference Equations to Model Nonlinear Cryptographic Sequences

TL;DR

This paper introduces a novel class of linear sequence generators based on cellular automata to model nonlinear cryptographic keystreams, analyzing key properties like period, complexity, and diversity.

Contribution

It presents a new approach using linear difference equations to model nonlinear cryptographic sequences, expanding the tools for cryptanalysis and sequence generation.

Findings

Sequences are solutions of linear difference equations

Analysis of period, linear complexity, and output diversity

Potential applications in symmetric cryptography

Abstract

A new class of linear sequence generators based on cellular automata is here introduced in order to model several nonlinear keystream generators with practical applications in symmetric cryptography. The output sequences are written as solutions of linear difference equations, and three basic properties (period, linear complexity and number of different output sequences) are analyzed.