Abstract:  Aiming at the shortcomings of traditional encryption algorithm, such as small key space and simple encryption structure, a doublechaotic image encryption algorithm which can greatly extend the encryption key is proposed. At the transmitting end, the image position mapping matrix is generated by the continuous chaotic system, and the image pixel information is added to the chaotic system. The encrypted image is transmitted over Ethernet and the pixel is synchronized and decrypted at the receiving end. The method utilizes the initial sensitivity of the chaotic system and the synchronization of the chaotic system to double encrypt the image. The structure of the doublechaotic image encryption system is complex and difficult to crack and has a great key space. The experiments show that the doublechaotic image encryption based on Liu chaotic system and discrete chaotic synchronization system can resist image statistical attack and exhaustive attack, and can be realized on Windows system.

Key words:    image chaotic encryption; continuous chaotic system; discrete chaotic system