On the security of block scrambling-based image encryption including JPEG distorsion against jigsaw puzzle solver attacks

摘要

Encryption-then-Compression (EtC) systems have been considered for the user-controllable privacy protection of social media like Twitter and Facebook. 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 for protecting 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 DES. In this paper, we evaluate the security of encrypted images including JPEG distorsion by using automatic jigsaw puzzle solvers.