Research on Chaos-Based Message Digest Method for Medical Images

How to design a fast and efficient method for message digest is always a hotspot in modern cryptographic researches. A message digest method based on chaotic map for medical images is proposed in this paper. At the beginning of this approach, an original message is grouped to generate an initial vector. And then the entire binary bits of the message are utilized for the chaotic map function which keeps iterating to switch among several candidates in order that the final digest is obtained. Meanwhile, this paper also provides a preliminary sensitivity analysis of the one-way hash function constructed by using chaotic map and a comparison to MD5 algorithm. The result shows that this kind of message digest based on iterations of switching chaotic map possesses good characteristic of confusion, diffusion and also higher level of secrecy compared with traditional or single chaotic map-based message digest method. Moreover, proposed method is easy to implement and therefore shows a promising way for message digest.