Block-permutation-based encryption scheme with enhanced color scrambling

Abstract

This paper proposes an extension of block-permutation-based encryption (BPBE) for the encryption-then-compression (ETC) system, which is more robust against some possible attacks compared to the conventional BPBE schemes. After dividing the original image into multiple blocks, the conventional schemes generate an encrypted image through four processes: positional scrambling, block rotation/inversion, negative-positive transformation, and color component shuffling. The proposed scheme achieves enhanced color scrambling by extending three of the four processes. The resilience against jigsaw puzzle solving problems can be consequently increased. The key space against brute-force attacks has also been expanded exponentially. Our scheme can maintain approximately the same compression efficiency compared with that of the conventional schemes.