Image Encryption Using Josephus Permutation And Filtering Diffusion

With the rapid development of digital technology,the increasing data is stored and transmitted as digital information.Digital image becomes the most commonly used data formats,because it is easy to store and carries a wealth of information.As a result,the security of digital image attracts broad attention.Recently,researchers have developed many image security technologies.Image encryption technique is an efficient technology to protect digital images,which is frequently used in important areas such as the financial systems and government agencies.Image encryption technique can encrypt the original image to be an unrecognized cipher-image.Only using the correct key,one can recover the original image.Traditional encryption technique is not suitable for encrypting digital image,because it fails to consider the property of digital image.Chaotic encryption has the risk of chaotic degradation,so that the chaotic performance is unstable on various digital platforms.Most image encryption technologies increase computational complexity to obtain reliable security performance.High computational complexity cannot meet the requirements of real-time encryption.As a consequence,it is necessary to develop a new image encryption algorithm with high security and low computational complexity.This thesis proposed an image encryption algorithm using Josephus problem and filtering diffusion.A Josephus scrambling is developed using the Josephus problem and it can shuffle image pixels to different row and column.Utilizing a irregular filter,the image filtering technology can spread tiny changes of original image to all the pixels of cipher-image.As the Josephus scrambling and filtering diffusion have good performance in achieve the confusion and diffusion properties,respectively,they can be combined to design an image encryption algorithm.Two rounds of Josephus scrambling and filtering diffusion can ensure the high security level of encrypted results.Simulation results show that the proposed image encryption scheme is able to encrypt different kinds of images into cipher-images.Security analysis demonstrates that it can resist various security attacks,and has better performance than several advanced image encryption algorithms.