An Image Bit Bit Encryption Algorithm Based On Joseph Traversal Mapping And Random Probability Encryption Event

In recent years, with the development of chaos theory, digital image encryption strategy based on chaotic is becoming the hot spot of research. In conventional image encryption algorithms, pixel permutation and diffusion are always two loosely coupled isolated stages and the encryption strategy is only related with key and irrelevant to plaintext image, which brings security risks.The research focus of recent image encryption is to improve the coupling degree between permutation and confusion, and combine the attributes of image itself with the encryption strategy. To address these problems, this paper proposed a bit-level image encryption algorithm based on Josephus traversing and probability of random encryption. The main research work are summarized as follows:1) In conventional image encryption algorithms, pixel permutation and diffusion are always two loosely coupled isolated stages and the encryption strategy is only related with key and irrelevant to plaintext image. To address these problems, a bit-level image encryption algorithm based on Josephus traversing and generalized Henon chaotic map is proposed, where Henon map variables combined with the SHA-1value of plaintext image as the key to drive Henon map producing modified Josephus traversing map’s start point, number space and number direction variables. The proposed algorithm used the generated Josephus traversing map variables to permutated plaintext image’s pixel bits. It added pixel bits diffusion stage.2) In conventional image encryption algorithms, different plaintext image always start the same encryption tactics, which brings the security risks. To address this problem, a bit-level image encryption algorithm based on Josephus traversing, Logistic mapping and probability of random encryption is proposed, where the SHA-1values of plaintext image combined with encryption parameters selected by the user as the key, according to the probability of random events, performing different encryption events to encrypt image in different encryption processes such as horizontal,vertical, main-diagonal and vice-diagonal direction of the bit-level permutation and confusion. In the proposed image encryption algorithm, different image and different encryption parameters are correspond to different encryption processings.Finally, this paper designed and implemented a digital image encryption software prototype system based on the Java language, the prototype system consists of image encryption algorithm and some typical security related digital image processing functions.