DS2B: Dynamic and Secure Substitution Box for Efficient Speech Encryption Engine

Mohammed F Tolba,Baker Mohammad,Hani Saleh,Yousuf Al Salami,Mahmoud Al-Qutayri

doi:10.1109/access.2021.3093247

Abstract

This paper proposes an efficient encryption technique based on Dynamic and Secure Substitution Box (DS2B) design suitable for IoT and resource-constrained platforms. The DS2B has the advantages of simple structure and good encryption performance. A different number of strong S-boxes could be generated with minor variations in the DS2B parameters. Performance analyses of the DS2B, including differential/linear cryptanalysis, bijective, nonlinearity, strict avalanche criterion (SAC), and bit independence criterion (BIC) have been presented where high nonlinearity, and low differential uniformity are achieved. Besides, a comparison with recent S-boxes is introduced which shows the robustness of the DS2B. To verify the DS2B, a speech encryption engine was realized on FPGA. Various security analyses were evaluated including the National Institute of Standards & Technology (NIST) statistical test suite, number of samples changes rate NSCR, mean square error (MSE), correlation, histogram, and spectrogram. In this work, the silence periods are encrypted in a way that makes them much harder to detect using the DS2B. The proposed encryption scheme achieved a throughput of 9.87 G bit/s, which is higher than previous work. A Xilinx Nexys 4 FPGA evaluation board was used for implementing and verifying the design.

Highlights

The security of IoTs continues to attract the attention of researchers due to their pervasive nature
PROPOSED DS2B METHOD This paper presents a method for obtaining dynamic and secure S-Box (DS2B) to be used in a speech encryption application
EXPERIMENTAL RESULTS The proposed encryption design was realized on Nexys 4 FPGA device XC7A100T, package CSG324, and tested as follows: All the speech files were stored in text files by using the MATLAB software

Summary

Introduction

The security of IoTs continues to attract the attention of researchers due to their pervasive nature. Implementing security algorithms on edge devices is a highly challenging task as they tend to have limited computation capability, small memory, and small power budget [1]. The projection of fifty Billion Internet-of-Things (IoT) devices by 2020 has pushed the energy harvesting research to study new solutions for improving the lifetime of batteries [2], [3]. The optimization of hardware implementation of IoT cryptographic engines is of paramount importance to address the issues of cost, throughput, and power budget. Most existing encryption designs for low-cost and low-power systems focus on optimizing the S-box, which has a significant effect on the area and energy cost [4], [5].

Methods

Results

Conclusion