A New Chaotic Image Scrambling Scheme Based on Spatial Bit-Level Map

Image scrambling is an important technique in digital image encryption and digital image watermarking. This paper proposes a new image scrambling algorithm based on chaotic sequence and spatial bit-level map. First, I used Logistic chaotic sequences to rearrange digital image pixels into one-dimensional (1-D) sequence, then the value of each pixel in the sequence was decomposed into k-bits which constituted a two-dimensional (2-D) bit matrix. Second, the spatial bit-level map was performed in the 2-D bit matrix to generate pixels with new values. Finally, the scrambling image was generated according to these pixels. This algorithm can scramble image based on the pixel’s position and the value and their corresponding probability. The experimental results show that this scrambling algorithm possesses perfect confusion properties and it can resist various attacks. Also it can apply to non-square image.