A Mixed Chaotic-cellular Automata Based Encryption Scheme for Compressed Jpeg Images

In this paper, we propose a new scheme for joint compression and encryption of digital images, based on cellular automata and selective encryption of quantized DCT coefficient. Using a key stream by a cellular automata mechanism, a subset of quantized coefficients is selected and then ciphered with the produced pseudorandom key-stream. Thus, we achieve a sufficiently robust security level, mostly against known plaintext attacks while preserving a high compression ratio. Several performance analysis including security analysis, speed performances and compression ratio are performed, and demonstrate the efficacy of the proposed approach with respect to existing ones.