The Research Of Encryption Technology Based On Chaotic Ciphers

With the development of our society, information resources are becoming important parts of people's daily lives. The safety of information then emerges in the top research field, among which the cryptography is the key technic. Because of the intrinsic relationship between chaotic systems and cryptosystems: strong dynamical proterties of chaotic systems imply strong cryptographical properties and strong cryptographical properties imply quasi-chaos. Chaotic systems, which act as natural cryptosystems, are applied into the cryptography. Since 1980s, the ideas of using chaotic systems to design new ciphers have attracted more and more attention.This article is about the research of encryption technology based on chaotic ciphers, involving the following two aspects:the applications of chaotic ciphers to audio encryption and image encryption.The main achievements of this article are:The way of generating a kind of decimal chaotic sequence is proposed. Then based on it an audio encryption algorithm is proposed by adopting module operation, which has nice encryption characters in the simulation. Another audio encryption algorithm based on zero dynamical nonlinear invertible system is studied and improved. In order to compare the encrypiton characters between the improved and the original algorithm, their applications to audio encryption are simulated, and the corresponding results are shown in chapter 3.Based on the discovery of the unsafty of an image encryption algorithm, the improved chaotic encryption algorithm resilient to a known/chosen plaintext attrack is proposed. The corresponding results show that the improved chaotic image encryption algorithm overcomes the original disadvantages, and is resilient to one known/chosen plaintext attack because of the adoption of wavelet transformation.