Effective transparent encryption scheme with scalable video communication

Abstract

Selective encryption conceals video content, rendering unwatchable. It gains over full encryption in terms of reduced encryption latency and reduced bandwidth. Many commercial applications of video encryption can go further because greater utility can be gained from transparent encryption, i.e. allowing prospective viewers to glimpse a reduced quality version of the content as a taster. The lightweight selective encryption scheme of this paper, when applied to scalable video coding, is well suited to transparent encryption. The paper illustrates the gains in reducing delay and increased distortion arising from a transparent encryption that leaves a reduced-quality base layer in the clear. This results when jointly encoding and encrypting input video by virtue of carefully selecting the entropy-coding parameters that are encrypted. The scheme is suitable for both H.264 and HEVC codecs. The scheme is demonstrated in the paper for H.264's Selected Content Adaptive Binary Arithmetic Coding (CABAC), the parameters of which are encrypted by a lightweight Exclusive OR technique, which is chosen for practicality and speed of encryption.