A novel low‐complexity scheme for improving security of NLFG‐based symmetric key cryptosystem using secure concatenated RS–QCLDPC code

Abstract

AbstractThe major requirements of a secure high‐speed communication system are low delay, good error performance, low redundancy, and good security. A simple nonlinear filter generator (NLFG)‐based cryptosystem is proposed in this paper to provide low delay with high security. Enhanced security is attained by embedding security in the channel encoder. An efficient concatenation of Reed–Solomon code and a secure quasi‐cyclic low density parity check code is used as channel encoder in the proposed cryptosystem to provide good error performance with low redundancy and to enhance security of NLFG with low structural complexity. The proposed efficient design of key‐based dense scrambling matrix and permutation matrix greatly simplifies the hardware structure. The novel method for generation of intentional error vector with modification of NLFG helps to reduce both the delay and power consumption. The integrated system is designed in such a way that both NLFG‐based stream cipher and secure channel coder complement each other to overcome the cryptographic weakness with a low hardware cost. The analytical and simulation results show that the proposed system attains significant security advantage against typical attacks and offers very good error performance. Copyright © 2015 John Wiley & Sons, Ltd.