With the rapid development of Internet technology, multimedia technology and network, all kinds of multimedia information can be spread conveniently and quickly on the network in different forms, and people communicate politically, economically, militarily and daily through multimedia information. However, there are also huge security risks in the transmission of multimedia information. Some lawless elements steal and maliciously destroy multimedia information through technical means from time to time, which brings huge losses to multimedia information holders. Digital image is an important part of multimedia information. The problem of digital image encryption is of great significance to protect the interests of digital image owners and promote the harmonious development of economy. Therefore, how to protect the security of digital images has become the focus of attention.

The research content of this topic is to study the information security of digital images based on the structural characteristics of digital images. The purpose of this project is to realize a higher security image information security algorithm, so it can encrypt and decrypt digital images, and it is a kind of cipher text that can not be recognized by a certain image method, and the original image will not be leaked during network transmission. There are many kinds of image encryption algorithms. Hilbert curve and Henon mapping are the themes of mixed encryption, which realize the spatial pixel scrambling of digital images and the gray transformation of digital images. The example shows that the encryption of the encrypted image has completely covered the content of the original image, and the encryption effect is good. Therefore, the hybrid encryption based on Henon mapping and Hilbert curve is a safe, effective and fast encryption algorithm.