Research And Implementation Of Digital Image Encryption Algorithm Based On Kaprekar Sequence

With the great development of Networks and Computer technology, the security of digital image becomes a more and more important concern. Features of digital image like huge amount of data and high redundancy make the encryption for digital image very different from encryption for common texts. Existing methods of image encryption include frequency-domain algorithms, spatial-domain algorithms and secret sharing technology, etc. This paper focuses on algorithms based on chaos system and spatial-domain. The conclusions are listed as follows.Firstly, a new concept of a chaos-like time series is proposed for a new solution to limit concise of chaos series computing. A method of time series analysis of the signal is put forward. According to Power Spectral Density (PSD), phase space construction, maximal Lyapunov exponent and Principal Component Analysis (PCA), it gets similar results with the classic Logistic chaos series.Secondly, a new parallel image encryption algorithm based on Kaprekar series is proposed. It separates the image into several bit level sub-image. Sub-images cypher themselves in parallel and by commutation with others they achieve a global permutation and diffusion. The algorithm succeeds in getting rid of redundancy and self-correlation of the image information by the bit level separation.Finally, A new self-adaptive image encryption framework is proposed which gives a good answer to the problem of differential cryptanalysis. The framework can be very sensitive to slight change of the image as well as user key by bringing in Hash function.