Abstract: Aiming at the low degree of image scrambling of the current single chaotic image encryption algorithm, which makes the encryption result vulnerable to known attacks and the problem of low security, a robust medical image encryption algorithm based on compound chaos is proposed. The feedback mechanism of image encryption is set as the theoretical support of algorithm implementation, and read the original image of robust medical. According to the establishment conditions of the chaotic model, a compound chaotic model is constructed. Choosing the Logistics chaotic map, generating a compound chaotic sequence and performing multiple iterations, scrambling and encrypting the pixels of the initial image of the robust medical image, replacing and diffusing, and generating the corresponding key to achieve the encryption of the robust medical image. Compared with the traditional encryption algorithm, the number of scrambling bits of the paper method is increased by 886 bits, that is, the degree of scrambling is increased by 8.7%, and the correlation of image sequences is low and the ability of anti attack is strong. The experiment results show that the security of this robust type of medical image encryption algorithm is high.

Key words: compound chaotic, robust image, medical image, encryption algorithm