Security Evaluation for Block Scrambling-Based Image Encryption Including JPEG Distortion against Jigsaw Puzzle Solver Attacks

TL;DR

This paper evaluates the security of block scrambling-based image encryption used in encryption-then-compression systems, focusing on JPEG distortion effects and vulnerability to jigsaw puzzle solver attacks.

Contribution

It provides an analysis of the security of block scrambling encryption schemes against puzzle solver attacks, considering JPEG distortion effects.

Findings

Block scrambling encryption has large key spaces but similar block correlations to original images.

JPEG distortion impacts the effectiveness of puzzle solver attacks.

Security evaluation includes analysis of encrypted images with JPEG compression against automated puzzle solvers.

Abstract

Encryption-then-Compression (EtC) systems have been considered for the user-controllable privacy protection of social media like Twitter. The aim of this paper is to evaluate the security of block scrambling-based encryption schemes, which have been proposed to construct EtC systems. Even though this scheme has enough key spaces against brute-force attacks, each block in encrypted images has almost the same correlation as that of original images. Therefore, it is required to consider the security from different viewpoints from number theory-based encryption methods with provable security such as RSA and AES. In this paper, we evaluate the security of encrypted images including JPEG distortion by using automatic jigsaw puzzle solvers.