Multimedia Encryption Algorithm And Implementation Based On Discrete Space-time System

With the development of digital information technology, information security has attracted widespread attention, multimedia encryption technology is one of the key technologies to ensure information security, its research has important significance. Chaotic cryptography is the current research focus, through constant development, has become an important branch of cryptography. Discrete space-time system is the focus of chaos research, it has a complex structure, large key space. Therefor, the application of the system is a good research in multimedia encryption.Based on existing knowledge of cryptography and discrete systems, I propose a new encryption algorithm which based on sequence effects of discrete space-time system, it will be used in image and video encryption, and proved to be a good encryption by simulation and analysis. The innovations of this work mainly include:1) Design a new key stream sequence generator by utilization of one-dimensional discrete chaotic system and two-dimensional discrete time-varying system, and detect the generating a plurality of key stream pseudo-random sequence properties by using single bit frequency detection, poker detection and correlation detection, simulation results illustrate the excellent performance of its pseudo-random, and it has more computational complexity, better encryption than the conventional method for generating a common key stream sequence.2) Propose a new sequence encryption algorithm based on the composite discrete chaotic system. The steps of encryption algorithm are presented in detail, and the algorithm is used to encrypt digital images. On one hand, the result of simulation experiment illustrates that the effect of encryption, key sensitive and other aspects are good, on the other hand, it proves that the algorithm has more space, better anti-attack statistics than existing common encryption algorithm.3) The above sequence encryption algorithm is used to encrypt AVI video files by using direct encryption. In order to improve real-time encryption process, this paper proposes a new improved algorithm. Steps of encryption algorithm and decryption algorithm are given in detail. Matlab simulation results show that the algorithm is excellent and has better real-time performance than traditional encryption algorithm.