Image Encryption Technique Based on Chaos Theory with the Introduction of Time Varying Parameter

For the shortcomings of single discrete chaotic map degradation under limited computer accuracy,little cipher key space and low security,a cryptographic algorithm based on time varying parameters has been proposed.The algorithm is composed of Chebyshev mapping and Logistic mapping,using a Chebyshev chaotic model to generate a chaotic sequence as a two stage Logistic mapping control parameter,and generating a chaotic two-dimensional transform matrix and image scrambling and pixel replacement.The scheme adopts system clock information as a time-varying keys to lock the two chaos mapping of initial parameters,which could realize one time once encryption.Due to the adoption of level 1 chaotic sequence to disturbance level 2 chaotic parameter,the two stage of chaotic sequences in different state space return migration,so as to solve the problem of digital chaotic sequences of finite precision effect.The simulation experiments show that the algorithm has good encryption effect with large key space,high speed,and safety.