A novel chaotic color image encryption / decryption based on triangular confusion

Abstract

In this paper image encryption algorithm based on confusion and diffusion using dynamic key space is proposed. Confusion of pixels is done by triangular confusion, method proposed in this work and diffusion is done by values obtained from logistic map iterations. An internal key generator is used to generate the initial seeds for the overall encryption scheme proposed, with these initial seeds, logistic map generates pseudo random numbers which are then converted into Confusion order (CO) for confusion. Confusion order is applied to the blocks which have undergone triangular confusion. The diffusion bits (DFB) are generated in parallel using the logistic map and manipulated with pixels confused according to confusion order. The image pixels are iteratively confused and diffused with CO and DFB respectively to produce cipher image in minimum number of rounds. This work focuses on key generation using logistic and tent maps with iterative reconstruction to secure the image. Chaos based method provides a dynamic changes for confusion and diffusion architecture in the image encryption. A single bit change in the key will dramatically change the result in the internal key generation structure proposed. The simulation results confirm that the satisfactory level security is achieved in three rounds and the overall encryption time is saved.