Abstract: A digital image scrambling algorithm based on chaotic sequence is designed after the analysis of Logistic map’s features. According to the pixels’ location, subsequences are acquired from the binary sequence mapped which is from chaotic sequence generated by Logistic map, and then they are made XOR operations with the binary sequences obtained by bits expanding of pixels’ gray value, at last the image is encrypted. The key codes of the algorithm are presented in the paper. Experimental results show that the algorithm has good scrambling effect with higher efficiency and safety.

Key words: chaos, image scrambling, secret key, Logistic map, bits expanding