SLEPX: An Efficient Lightweight Cipher for Visual Protection of Scalable HEVC Extension

Rizwan Ali Shah,Mamoona N Asghar,Nadia Kanwal,Saima Abdullah,Martin Fleury

doi:10.1109/access.2020.3030608

Abstract

This paper proposes a lightweight cipher scheme aimed at the scalable extension of the High Efficiency Video Coding (HEVC) codec, referred to as the Scalable HEVC (SHVC) standard. This stream cipher, Symmetric Cipher for Lightweight Encryption based on Permutation and EXlusive OR (SLEPX), applies Selective Encryption (SE) over suitable coding syntax elements in the SHVC layers. This is achieved minimal computational complexity and delay. The algorithm also conserves most SHVC functionalities, i.e. preservation of bit-length, decoder format-compliance, and error resilience. For comparative analysis, results were taken and compared with other state-of-art ciphers i.e. Exclusive-OR (XOR) and the Advanced Encryption Standard (AES). The performance of SLEPX is also compared with existing video SE solutions to confirm the efficiency of the adopted scheme. The experimental results demonstrate that SLEPX is as secure as AES in terms of visual protection, while computationally efficient comparable with a basic XOR cipher. Visual quality assessment, security analysis and extensive cryptanalysis (based on numerical values of selected binstrings) also showed the effectiveness of SLEPX's visual protection scheme for SHVC compared to previously-employed cryptographic techniques.

Highlights

In terms of bandwidth utilization, the main content that is currently transferred over the Internet is visual multimedia [1], i.e. video and still images, with applications such as Videoon-Demand (VoD), video conferencing, video phone, and telemedicine
To avoid any impact on encoder/decoder synchronization Selective Encryption (SE) is applied at the final entropy coding stage of Scalable HEVC (SHVC) with careful choice of encrypted syntax elements
The proposed privacy protection solution works by selecting significant syntax elements i.e. Motion Vector Differences (MVDs) signs, as well as the NZ-Transform Coefficients (TCs) signs and absolute value of the NZ-TC suffixes from the Context Adaptive Binary Arithmetic Coding (CABAC) coder at each SHVC layer

Summary

INTRODUCTION

In terms of bandwidth utilization, the main content that is currently transferred over the Internet is visual multimedia [1], i.e. video and still images, with applications such as Videoon-Demand (VoD), video conferencing, video phone, and telemedicine. Because the format of an encrypted (and compressed) bitstream matches the specification of a standardized codec such as HEVC and its extensions, it can be decoded at intermediate devices in a network or while at rest in a cloud, without the need for the decryption that occurs with full encryption. The current paper proposes a new lightweight encryption scheme, which is decoder format compatible and is applicable as SE for SHVC encoders.

BACKGROUND

SUMMARY OF SLEPX FEATURES SLEPX has the following features:

RESULTS AND ANALYSIS

VIDEO QUALITY METRICS

CONCLUSION