软件注册机制研究与实现

本文借鉴前人的研究成果,通过对已存在的软件注册机制优缺点的比较,设计出一种合理的,切实,有效的针对网上发布软件的软件注册机制,并对它进行分析和评估。本软件注册机制以序列号和注册码的形式完成注册过程。序列号和注册码的产生和计算机硬件信息相关,达到一机一密,RSA算法参与序列号和注册码的生成。软件注册过程需要服务器参与,服务器生成注册码,并存储用户注册信息。     

超混沌双向认证的隐私信息安全加密算法

随着物联网的普及,其信息安全加密方法也受到越来越多的关注,为了提高物联网的隐私保护能力,本文针对现有的信息安全加密算法的缺陷,提出了一种基于超混沌双向认证的隐私信息安全加密算法。首先对超混沌序列的随机性进行了分析验证,然后将超混沌序列应用于信息加密中,分别阐述了身份双向认证的隐私信息安全加密算法的注册过程和认证过程。算法实例仿真结果表明,本文提出的算法相比较Hash算法,加密效果更好。     

基于DES对称加密体制的探讨

DES是一个分组密码算法,它使用56位的密钥,以64位为单位对数据分组进行加密和解密。报文分组后,明文与密文的长度相同,均为64位。DES是一个对称密码体制,加密与解密使用相同的密钥,同时,DES的加密和解密也使用同一算法(在硬件与软件实现时,有利于加密单元的重用)。对称加密体制的DES所有保密性均依赖于密钥,密钥是保证对称加密体制安全性最核心的元素。该算法自问世以来在很长的一段时间内,经受住了无数密码爱好者和科学家的研究与破译,目前在民用领域得到了广泛应用。     

一种基于Web服务器的文件加密授权保护系统设计与实现

鉴于Web服务器文件访问中存在的安全隐患,比如文件截取、文件篡改等问题,设计了一种基于Web服务器的文件加密授权保护系统。该系统通过与web服务器硬件特征码绑定,实现对Web服务器中文件进行加密存储以及对加密文件的修改和访问。系统设计中,采用多种传统的文件加密算法生成加密密钥并实现文件加密和解密功能。其中,利用MD5算法实现由硬件机器码转化生成初始加密密钥的功能,利用RSA算法实现由初始加密密钥转化生成授权密钥的功能,利用RC6算法实现文件的加密和解密功能。     

Hill密码中剩余阵的逆矩阵的求法及Matlab实现

在计算机网络中,为了保证数据的保密性和可靠性,需要对数据进行加密与解密。本文先介绍了Hill密码算法,指出Hill密码密钥矩阵即剩余阵的逆矩阵存在的充要条件,最后较详细讨论了求剩余阵的逆矩阵的算法及其Matlab程序,从而可通过Hill密码对信息进行快速加密与解密,实现用户信息安全保护。     

一种文件透明加解密标识嵌入方法研究

设计了一种包含多种信息的加密标识数据结构,并将该结构嵌入到文件头中,解决了文件透明加解密系统中加密标识的设置问题。     

基于色散评价的量子通信变密钥混沌加密方法

量子通信中的密钥设计是整个量子通信系统安全性的重要保障,传统的密钥设计方法采用固定密钥,无法实现变密钥加密,所以密钥和通信内容被破解的概率很高。提出一种基于色散评价的量子通信变密钥混沌加密实现方法,每次通信时,从混沌学的角度提取所有待通信数据的深层次特征,然后形成本次通信的加密和解密密钥,随通信内容的不同,系统密钥实时变化,在接收端,通过密钥和通信内容的混沌匹配来实现解密,并采用色散特性对加密效果进行评价。通过一组通信内容进行混沌加密性能测试,结果显示,基于色散特性衡量下的混沌加密特性安全性较传统方法大大提高,加密文本被破解的概率是0.0011%。     

基于扩展的N维魔方加密算法的设计与实现

利用魔方旋转的思想 ,将三维魔方扩展到N维 ,构造并实现了扩展的N维魔方加密解密算法。发现扩展的N维加密解密算法有其运算速度快、密钥空间大的优势。     

基于混沌理论和DNA序列运算的古籍数字化版权保护及实现

[目的/意义]旨在更好解决古籍高清数字化图像在互联网上传播后存在的版权和高仿真复制问题,提出基于混沌理论和DNA序列运算的加密算法.[方法/过程]该算法以混沌理论为基础,结合DNA序列运算,对图像数据进行像素值替代扩散,再通过图像置乱替换像素值位置,完成整个加密过程.[结果/结论]测试结果表明,该算法加解密效果良好,能...     

浅谈量子密码技术

随着网络技术的快速发展，大量敏感信息需要通过网络传输，人们需要对自己的信息进行保护以免丢失或遭受攻击。密码学为我们提供了有力的保证。用户用一个加密密钥对自己的数据进行加密，加密后的数据只能被相应的解密密钥恢复，非法用户则因为没有解密密钥而“看不到”真实数据。通信双方事先协商好密钥就可进行秘密通信。     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Stern-Gerlach effect goes chiral

Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）.