A Space-bit-plane Scrambling Algorithm for Image Based on Chaos

Image scrambling is an important technique in digital image encryption and digital image watermarking. This paper's main purpose is to research how to scramble image by space-bit-plane operation (SBPO). Based on analyzing traditional bit operation of individual pixels image scrambling method, this paper proposed a new scrambling algorithm. The new scrambling algorithm combined with SBPO and chaotic sequence. First, every eight pixels from different areas of image were selected according to chaotic sequence, and grouped together to form a collection. Second, the SBPO was performed in every collection and built eight pixels of the image with new values. The scrambling image was generated when all pixels were processed. In this way, the proposed algorithm transforms drastically the statistical characteristic of original image information, so, it increases the difficulty of an unauthorized individual to break the encryption. The simulation results and the performance analysis show that the algorithm has large secret-key space, high security, fast scrambling speed and strong robustness, and is suitable for practical use to protect the security of digital image information over the Internet.