Multi-Layer QCA Shift Registers and Wiring Structure for LFSR in Stream Cipher with Low Energy Dissipation in Quantum Nanotechnology

Abstract

Pseudorandom numbers (PRN) are used in various cryptographic applications, such as cryptographic protocols and stream ciphers. The most efficient hardware method used to generate PRNs is to use a Linear Feedback Shift Register (LFSR) structure, which is generally composed of a Shift Register (SR) and an XOR gate. The most important factors in designing the entire LFSR structure are design cost and energy efficiency, which are highly dependent on the SR structure. In the proposed study, the structural characteristics and problems of existing various types of SRs are presented, and new multi-layered serial-in-serial-out (SISO) and parallel-in-parallel-out (PIPO) SRs are proposed. In addition, we compare and analyze the area-time complexity, design cost, and energy dissipation through simulation using QCADesigner and QCADesigner-E. As a result, the proposed SISO and PIPO showed a performance improvement of more than 27% compared to the existing structure, which showed the best performance, and showed energy dissipation reduction rates of about 65% and 59%, respectively. In particular, we proposed multi-layer wiring that can reduce energy dissipation and verified through simulation that it can save up to 24.8%.