PGP加密系统及其安全性

PGP是目前正在流行的电子邮件加密算法,它具有加密强度高、加密速度快和密钥分配安全的特点,是理想而且实用的电子邮件加密算法.本文论述了PGP的工作原理和密钥管理,并就PGP可能存在的安全缺陷进行了探讨.     

基于PGP系统的电子邮件安全机制的实现

为了保障电子邮件在传输中的安全性,介绍了PGP系统所采用的加密算法及认证机制,简要介绍了利用PGP系统实现在发送方对电子邮件的加密以及签名,在接收方对电子邮件的发送方进行验证以及对密文进行解密。     

电子邮件的安全性分析

本文就电子邮件系统的安全性进行分析。探讨了电子邮件的安全问题,指出其不安全的内在原因,提出了安全电子邮件应具有的四种具体功能。由于PGP侧重个人目的的电子邮件安全,最后对基于RSA公钥加密体系的邮件加密软件—PGP进行了详细的分析。     

椭圆曲线密码技术在电子邮件加密中的应用和实现

指出被广泛使用的电子邮件加密软件PGP（Pretty Good Privacy）的不足。讨论了最新的椭圆曲线密码体制ECC（Elliptic Curve Cryptography）与RSA相比的优越性。并把椭圆曲线密码技术应用于电子邮件加密系统，设计并实现了一套电子邮件加密软件。与PGP相比，它的安全程度更高、技术更先进。     

如何发送和接收安全电子邮件

该文主要介绍了如何利用个人证书及PGP(Pretty Good Privacy)发送、接收安全电子邮件并分析比较S/MIME和PGP的主要区别。     

浅析PGP软件及其应用

论文主要介绍了PGP软件定义及工作流程,再简述了工作原理,最后以银行系统为例论述了PGP软件在电子邮件方面的应用情况。     

PGP在安全电邮系统中的改进实现

PGP,全称Pretty Good Privacy,是一个基于RSA公钥加密体系的电子邮件加密软件.它可以对电子邮件进行加密和签名,防止非授权阅读并确定发信人的真实身份.PGP采用了对称和非对称混合的加密算法、单向散列算法以及较为审慎的密钥管理机制.本文中,作者分析了PGP的原理和密钥管理机制,根据其弱点提出了一种改进方案(iPGP).     

网络安全领域的传奇——小记NAI公司的PGP和它的作者

所谓PGP就是Pretty Good Privacy,它是文件和电子邮件加密的典范,在世界上拥有四百多万的用户。目前最高版本的PGP软件是由NAI推出的PGP Total NetworkSecurity,它可在本地、内部网、外部网和公共Internet上自动执行保护数据资产的公司关键任务。 作为PGP技术的发明人,Philip R.Zimmermann在网络上一直具有强烈的传奇色彩。因为他不仅发明了PGP这种先进的网络加密技术,更为此受到为期三年的犯罪调查。其原因在于PGP,自1991年作为自由件推出后,在世界范围内得到迅速普及,美国政府认为这违反了美国对密码软件的出口限制,于是一再阻挠Philip和他的PGP技术在网络上的推广。但PGP仍发展成为世界上使用广泛的电子邮件加密软件。在美国政府于1996年初撤消诉讼后,Zimmermann成立了PGP公司,而到1997年12月,PGP公司成为了美国网络联盟公司的一个重要成员。Zimmermann现任美国网络联盟公司高级董事,并作为网络联盟一名独立的密码技术顾问继续从事网络安全方面的研究。     

E-mail安全协议PGP

本文从单钥密码IDEA算法、双钥密码RsA算法、单向杂凑算法MD5算法等分析了安全电子邮件协议PGP的实现原理和实现流程;描述了PGP所提供的安全业务;并从RSA、IDEA、MD5、随机数等安全性方面分别研究了PGP的安全性能.     

电子邮件系统中PGP的改进研究

本文针对电子邮件安全系统中现行使用的PGP,提出了一个改进的PGP方案,新方案中将ECC和AES有机结合,并新增加了时间戳技术,不仅极大增强了E-mail的安全性,而且加密次数也减少了,同时也解决了目前PGP中加解密速度和安全性不能兼顾的问题。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate