public-key Encryption Based on Torus Automorphisms

Chaotic maps with its characteristic are very useful in cryptography, however, compared with wide application in symmetric system, the research about chaos in public-key encryption system is still few. Through analysing the period of toms automorphisms which is a prototype of chaotic map, and making use of the framework of the traditional public-key algorithm RSA, the authors propose a chaotic public-key encryption algorithm based on toms automorphisms. Its security is based on the intractability of the integer factorization problem as RSA, and it is able to resist the chosen-ciphertext attack against RSA and easy to be implemented.     

An field programmable gate array implementation of an image encryption algorithm based on a discrete chaotic map

Software encryption cannot satisfy real time requirements for multimedia applications which usually involve large volumes of data. To address this problem, an field programmable gate array(FPGA) implementation of the Cyclone EP1C6 for a Kolmogorov chaotic map based image encryption algorithm MASK was proposed. The algorithm was composed of four basic parts: Mixture, key Add, S box and Kolmogorov chaotic map transforms. These parts specifically act on the image as follows: diffusion, applying secret keys, nonlinearity, and permutation. The correlation of adjacent pixels, UACI and the key space of the system subsequently were studied. The source occupation proportion of the hardware was calculated statistically and showed low occupation. Among the advantages of the proposed system are high security, fast encryption speed, and low hardware resources consumption. The proposed system is suitable for implementation in inexpensive FPGA.     

随机区间置换的安全算术编码及应用

基于压缩编码的加密方式能够同时完成加密和压缩的功能,通过压缩减少了信息的冗余,同时引入加密使对试图推测出明文信息和找到密钥的攻击具有非常好的鲁棒性。提出了一种基于随机区间置换的安全算术编码,在编码过程中通过随机密钥保证图像压缩编码的安全性,且不影响编码的效率,使其方便在网络中安全传输。实验结果和安全性分析表明该安全算术编码有较好的安全性和加密效率。     

Logistic map controlled secure arithmetic coding and its application in image encryption

A logistic map controlled secure arithmetic coding is proposed, the Logistic map is used to control the order of the symbols in the model and change the probabilities of the symbols, which is applied to the image encryption. The proposed scheme makes the image transmit more secure and comfortably on the Internet, and that is done at little expense in terms of coding efficiency. In the coding process, it ensures the uniformity of the model being changed by the chaotic sequence, thus to meet the security requirements of image compression. The algorithm can be applied to any arithmetic codec based on multimedia data including video, image and audio. Its most strength compared with other cipher mode is that, there is a significant reduction in the redundancy of information during the compression process, and it is robust when attempting to estimate the information of the image and discovering the key. The scheme can effectively resist differential analyses from both cryptography and coding.     

Design and Implementation of Chaos Encrytion Algorithm based on Logistic Formula

The security of stream cipher, which is known as one of the main cipher techniques, dependents completely on the quality of generated pseudo-stochastic sequences. Chaotic systems can produce the pseudo-stochastic sequences with the properties of excessive dependence on initial conditions and the difficulty in forecasting, therefore, these systems are suitable to the stream cipher. A new encryption algorithm is proposed by analyzing the principle of the chaos encryption algorithm based on logistic formula. Moreover, the security and performance of the proposed algorithm is also estimated. Finally, an example is given to demonstrate our method via the Visual C++.     

Realizing Key Schedule of Rijndael Algorithm Integrating with Chaos

Encryption is an important method which is used to protect the information of an individual and enterprises and the secret of nations. Rijndael algorithm is the new advanced encryption standard, and has extensive application foreground because of its much merit. Modem encryption algorithms are based on keys. However, so far few of people research into the key schedule of rijndael algorithm and especially do research on the generation of its initial keys. This paper researches into the mapping of Logistic, makes use of a chaos algorithm to produce initial encryption keys because it can create chaos sequences of high randomicity. Further more, corresponding CPLD implementation is given.     

Application of Chaos Theory in Cryptography

Cryptography has the crucial importance in modern info-society. The merits of chaos have brought a new means for the design of cryptography. As a brilliant achievement of modern cryptography, chaotic cryptography has great potential and becomes more and more popular in info-security field. The corresponding problems about cryptography and chaos theory are discussed in detail. The theory and method of the chaos-based cryptography is analyzed, the recent research development of chaos-based cryptography is expatiated. Both advantages and disadvantages of chaos-based cryptography are summarized and the future research trends are outlined.     

Mouse with Capablility of Fingerprint Identifying

The mouse is developed with the purpose of providing reinforcement of database security for computer users, whose validity can be verified by taking advantage of the fingerprint identity, which is the uniqueness, immutability biological characteristic of human body. By one-by-one matching algorithm, rendering between pressured data and field acquisitions of finger print image, the vital heart of dactylogram verification with the mouse is realized. The mouse has been made possible by taking account of the roomy space within mouse,tiny chip patch for fingerprint identification and together with small size of available microprocessors. The mouse can be used as an normal pointing device while maintaining the capability of user identity distinguishing. The usage of this device is very easy and it is reliable. Development of this device mainly comprises of the hardware development, driver development, application software development, and the installation of network security verification center. The purpose, principle and system design of the mouse is introduced, while characteristics and applications of the device are also presented.     

Method of High Accuracy Phase Measurement Based on the MCS-51 Single-chip Computer

Phase is a kind of important wave parameter of periodical signal. Making use of the combination of MCS-51 single-chip computer and external circuit and using its fiat resource fully, this paper has realized the high accuracy measure of phase difference by using the precision measurement technique such as over zero appraisal phase method, fill count by the pulse of high frequency and multiperiods etc. It also introducs systematic principle and the realization method of hardware and software emphatically.     

Construction of substitution boxes based on tangent delay ellipse reflecting cavity mapping system

Based on the good chaotic properties of tangent delay ellipse reflecting cavity mapping system (TD ERCS), a kind of novel substitution boxes were constructed. The cryptographic properties, such as bijection, nonlinearity, strict avalanche, independence of output bits, the differential approximation probability and the nonlinear approximation probability of the S box are analyzed. The investigation method for the strength of the S box with the discrete chaotic system proposed by Kocarev is discussed. Theoretical analysis and backtesting results show that the method is efficient and easy to put into practice, while the constructed S boxes show better cryptographic properties than the S boxes based on other chaotic system, which can be used to improve the existing encryption scheme.     

Digit Weight and Development of a Virtual Noise Analyzer

Traditional noise octave analyzers consist of filter network and weight network based on hardware. In order to realize a noise octave analysis by software, a digit weight method based on FFT is proposed. Using the method, digit weight and digit system error modification for virtual noise octave analyzer can be realized. Because of digit weight and digit system error modification, precision and stability of the instrument can be improved greatly. As an application, which combines the method of digit weight with the technique of digit system error modification, a low cost and high precision virtual real time noise octave analyzer is developed.     

Line-tracking Technology and It'' s Application in the Contest Robots

There are important significations in the industrial production and academy research to manage the intelligent robot walks along the scheduled track. This paper combines the development of the contest robot, and discusses the reliable method to realize this function. By the discussion on the chosen of the key sensors, sensing principle, realization of resisting the interference from surrounding light and self-adaptation adjustment algorithm, the authors analyz the linetracking technology on contest robots precisely. Practice indicates that the method of the hardware and software stated is concise and reliable, and there are some reference significations in the application research of the intelligent robot.     

基于主成分分析法的重庆市九龙坡区

为了研究影响区域土地利用的动态变化及其驱动机理,以期对区域土地利用的可持续发展提供决策支持。通过分析1999-2008年10年间九龙坡区土地利用数据,阐述该区域土地利用变化情况,并借助SPSS软件对驱动因素进行主成分分析。结果显示,近10年来影响九龙坡区耕地利用变化的主要驱动因素为人口、经济结构和农民福利;影响建设用地利用变化的主要驱动因素为人口、经济发展和农村居民点用地集约化程度。     

Design of Testing System for ABS Test-bed

This paper discusses the structure, design and key techniques of testing system, and expounds the design and development of hardware and software based on virtual instrument technology. The design of hardware includes signal conditioning module and data acquisition module. The design of software includes interface program and upper layer program. Combining the hardware and software effectively, a testing system for ABS test-bed is set up, which has multifunctions of developing, debugging, inspecting and performance valuing to ABS. Having crucial meaning in engineering, the development of this testing system will make ABS tested in the lab mainly, thus improve the security and make the test more economical.     

Design of the PC/104 Bus Mode Multi-channel Analyzer

This paper expatiates on the bus structure and develop the bus mode Multi-Channel Analyzer (MCA). The nucleus of this MCA is the PC/104 embedded computer, and it introduces the bus communication to realize system and data communication. It may realize data collecting and showing in the field, because the bus mode is rapid. At first, on the hardware we introduce CMOS components, this reduces power, volume and weight. These make it adapts to use in the field; besides, on the software we adopt C and assembly language to program in order to improve conversion speed. At the same time, single-task DOS operating system is infroduced, which makes the software run more steadily, operate more simply. By means of testing on the spot it can normally work, so it suitable to work in the field.     

Design of nondestructive examination system for bridge cables surface defect

Aiming at the drawbacks of the current detecting methods, a nondestructive examination system design for bridge cables based on high speed digital signal processors chip DM642 is presented, and the hardware platform of the system is built. This examination system mainly consists of four parts: the image defaults acquisition part, DM642 hardware platform, creeping part and defaults locating equipment. The designed system is tested on the hardware platform based on digital image processing algorithm. The experimental results show that the detecting system has the advantages of high stability and reliability, real time, mass storage, and nondestructive examination, etc. This system uses high technology and has significant meaning on detecting the current bridge cables health, furthermore, this method can be used in other examination fields.     

林业专题图数字水印版权保护研究

针对林业专题图制作过程复杂、成本高、迫切需要进行版权保护的问题,分析了JPEG图像压缩的不变属性,在此基础上提出了一种DCT域数字水印算法,该算法将水印信息嵌入到JPEG格式的林业专题图像的中高频系数当中。结果表明：因为水印信息是嵌入在中高频系数上,所以不仅嵌入的水印信息不可感知性良好,而且水印的嵌入容量也有所增加;即使对加密林业专题图进行有损压缩时使用高于预设值的质量因子,此算法仍然能够完全一致地提取出嵌入的水印信息,并且对各种噪声干扰都具有较好的鲁棒性。     

山东省小麦生产技术效率变化特征及结构优化

本文基于非参数方法通过构建双产出模型,在对山东省小麦生产技术效率测度的基础上,具体分析其历时特征和小麦生产资源配置结构优化策略。结果表明,山东省小麦生产技术效率1996年以来先是大幅度下降而后缓慢上升,其主要制约因素是规模效率。研究所体现的政策含义是,政府部门在进一步加大对耕地保护的同时,适时进行制度创新,激励粮农通过技术进步和合理的投入,提高耕地利用效率和产出效率,进一步加快农村剩余劳动力转移,加强农业基础设施建设,使转型期中国耕地资源的利用实现从粗放型向集约型转变,从而确保国家粮食安全和粮农收益最大化双重目标的实现。     

Research on Cooperative Design Network Security Based on IP-VPN

As the important method and instrument of agile manufacture,the technology of distributed collaborative design and manufacturing has become the hotspot of manufacturing. The basic concept and key technologies of IP_VPN are introduced in this paper,and a collaborative design network model based on IP_VPN is presented. Distributed collaborative design is a multi_user,multitask involved system, which is consisted of lots of collaborative processs,so the network security is the key of distributed collaborative design. We research on the security of collaborative design network based on IP_VPN, hence get a conclusion:we can construct an economical?practical and secure collaborative design network system by the application of data encryption,user authentication and access control based on the role,etc.