An Improved Lossy-Encryption System for Still-Image Data Based on the Quaternion Multiplication and Robust Chaos

In this paper, we propose an improved lossy-encryption system based on a previously vulnerable one. The original system is first analyzed for potential drawbacks, and then a new system with enhanced security level is proposed. The main strength points of our proposed system reside in the key generation which is based on robust chaos and a fast hashing scheme, and the lossy property of the scheme which contributes to make a good diffusion and confusion. Security analysis shows that the system possesses good statistical properties and it can resist the discussed attacks.