The Study of Image Block Encryption Update Algorithm Based on Dynamic S-boxes Mechanism and Its Blocks Optimization
Mingxi Wu · Science Technology and Engineering · 2014
In order to the maximum number of blocks encrypted by the current image blocks encryption algorithm is determined,and guaranted the keys used by the each S-boxes during the diffusion can be real-time update, the dynamic S-boxes mechanism and cipher feedback mechanism were proposed,and introduced the single distance to optimize the maximum number of blocks encrypted by each S-box. The sets of dynamic S-boxes were generated by the generation method of dynamic S-boxes,and the blocks were permutated by the S-boxes set according to the left cyclic shift operation. The permutated blocks were encrypted by different S-boxes according to the substitution and shift operation. The cipher feedback was used to change the iteration times of chaotic map to get a new dynamic S-boxes set for enhance the relations between the plaintext and S-boxes as well as ensuring this algorithm can real time update. Finally the MATLAB simulation platform was used to test this algorithm. The results showed that the S-boxes have a higher linear property; and compared with other algorithms,this algorithm had a highest security, huge key space and strong anti-attack capability.