JPEG Image Ciphering Based on Chaotic Encryption

This paper proposes a chaos-based encryption method that allows conditional access to privacy-sensitive regions in Joint Photographic Experts Group (JPEG) images. Our goal is to encipher the confidential content in a way that guarantees high resistance to common attacks without severely compromising the encoding speed and bitrate cost. The encryption mechanism comprises two modules: chaotic confusion and diffusion; the first module is governed by means of nonlinear shuffling applied on the quantized AC (Alternating Current) coefficients belonging the region of interest (ROI), while the second module is ruled by means of XOR operation that encrypts the shuffled components using a cumulative one-dimensional chaotic map. The whole cryptosystem is controlled by the chaotic sequences generated by chaotic maps. Experimental results demonstrate that the proposed cryptocompression scheme is proven to be effective in balancing the trade-off between robustness and hiding ability while guaranteeing reversible recovery of the protected data.