Double verifiable image encryption based on chaos and reversible watermarking algorithm

Abstract

The integrity of image is the premise for various applications. The existing image encryption algorithms rarely have the function of verifying the integrity for the decrypted image. To cope with this problem, a novel double verifiable image encryption algorithm based on chaos and reversible watermarking is proposed. In the proposed scheme, the 256-bit hash of original image is firstly calculated and embedded into the pixel-level permutated image by histogram shifting based reversible watermarking, then image diffusion is conducted based on hyper-chaos. Lastly, the hash values of diffused image and original image are embedded into the diffused image itself using difference expansion based reversible watermarking, thus the verifiable encrypted image (VEI) is generated. The secret key of the algorithm depends on the image itself; this makes the brute-force attacks impossible, and the application of reversible watermarking guarantees that the integrity of the VEI and decrypted image can be verified. Experiments and analysis are given to demonstrate that the proposed scheme has better performances, and it has good potential in the application of medical and military image.