关键词: 低密度奇偶校验编码, 混沌系统, 图像加密, Henon映射, Arnold变换

Abstract: To improve the security and reliability of image transmission, an image encryption algorithm based on combination Low Density Parity Check (LDPC) coding with chaotic system was proposed. Firstly, the algorithm used parity encoding to extend pixels' value of image into 10 bits and calculated its deviation acted as chaotic initial value. Secondly, Arnold transformation was used to scramble the positions of image pixels and Henon mapping was used to diffuse the values of pixels. Finally, the high 2 bits were separated from 10 bits of pixel value and transmitted faultlessly by LDPC code, the other 8 bits acted as the encryption result. The experimental results show that the proposed algorithm has strong sensitivity to the keys and plaintext, possesses favorable avalanche effect, and it can resist plaintext attack and differential attack effectively. Moreover, the encryption result has strong ability of resisting cutting and noise attacks.

Key words: Low Density Parity Check (LDPC) coding, chaotic system, image encryption, Henon mapping, Arnold transformation