Block Sampling Algorithm of Image Encryption Based on Chaotic Scrambling

Base on the randomicity and initial value sensitivity of Lu chaotic sequence, dividing the original image into blocks, carrying out the gray scrambling and location scrambling on each team of the pixel points, making their location and grey distribute evenly at the same time, it can accomplish the encryption of a image. Using Matlab to simulate, the result indicates that this algorithm has great secret key´s space, and it also has the ability of resisting statistic attack and damage. For 256 times 256 BMP image which data size is 192 k, encryption cost approximately 0.152 s and decryption cost approximately 0.161 s.