Security analysis and modification of a chaotic encryption system

A type of digital chaotic encryption system was proposed in Ref. [1] which uses a class of 1-D piecewise linear (PWL) map to realize chaotic encryption and decryption system through the inverse system approach. In the general with the input terminal. In this paper we show that this cryptosystem can not frustrate chosen-cipher text attack. A type of chaotic encryption system based on self-synchronizing stream cipher is proposed. This system can avoid chosen-cipher text attack and has higher security.     

Robust gray-image face detector based on local statistical features

An efficient training framework for gray-image face detection was presented. Our system includes two stages.In the first stage, the pattern rejection theory is used for features selection. The local Haar-like wavelet features used as rejection features to reject those patterns are not faces obviously. In the second stage, the Kullback-Leibler divergence in information theory is applied to choose more effective features further and to construct hierarchical classifier. The probability functions of two classes are estimated by joint-histograms. Final decisions are made according to the likelihood ratios between two classes. The experimental results show that our system is the same robust and efficient as the best reported methods, while the training efficiency is higher than others.     

基于参数跳动和扰动的混沌保密系统的理论设计

提出一种基于参数跳动和扰动的混沌保密方法．通过随机改变混沌映射的参数来提高混沌映射的复杂性；同时在有限精度实现时，通过引入随机扰动序列使得输出的混沌序列具有良好的自相关性、均匀分布特性和随机统计特性等．理论研究和模拟结果表明，该混沌序列加密方法具有较好的保密性并且便于软硬件实现．     

Secure property of chaotic encryption system based on chaotic synchronization

1 .INTRODUCTIONAsanapplicationofchaostheory ,securecommunica tionshavebeenstudiedsincetheearly 1990s .Anumberofsecurecommunicationschemesbasedonchaossynchronizationareproposed .Somecryptanaly sisonthesesecuresystemsispresented [1,2 ] .Theyarebasedonpartia…