安全通信

Secure Socket Layer protocol is the most widely deployed protocol for securing communications on the Internet network.

安全套接字协议是Internet上部署最为广泛的保证安全通信的协议。

Firstly, this paper puts forward an improved authentication and key distribution scheme for internet environment, in which we adhibit multilevel authentication center, encryption technology of DES, RSA and one-way function to actualize the safety of communication among the different user on network and reduces the workload of the authentication institution; at the same time, this scheme can also assure the security of network. Besides, it use the temporary symbol and the responds" sign of both-side correspondent to replace time stamp and applies them to internet communication to countercheck "rebroadcast attack and accordingly resolves the problem that it needs synchronization for network clock.

本文在首先提出一种改进的Internet网络环境下的认证及密钥分配方案，该方案考虑采用了多级认证中心，DES、RSA和单向函数加密机制，实现了网络上不同用户间的安全通信，降低了网上认证机构的工作量，同时也能够保证网络的安全性；并用通信双方的临时标志和响应者标识来代替时间戳应用于Internet通信中以防止"重播"攻击，从而解决了以往需要网络时钟同步这一难题。

The system is composed of trust model, structure and function design, certificate database design, and implements the core functions of a standard CA system including signing, issuing and revoking certificates. The security communication modular of the system is based on the SSL Protocol to enhance the security of system communications. Besides, the kernel functions of the system are packed into DLL library, including symmetrical encryption algorithms, digest algorithms, digital signature algorithms and certificate operations such as certificate request, certificate building, certificate format conversion etc.

本文的主要工作是：在研究PKI相关技术的基础上，设计了企业CA系统方案，包括信任模型、结构和功能设计、证书库的设计；实现CA系统中最为核心的数字证书管理，提供数字证书的签发、注销和发布等各项功能；实现了基于SSL协议安全通信模块，增强了系统通信的安全性；系统采用动态链接库技术封装了对称加密算法、数字摘要算法、签名算法以及证书处理(包括证书请求、证书生成、证书格式转换等功能)，以动态链接库的形式提供调用接口，成为应用的安全基础设施。

At present, there are two branches in the research of database security technology, which are secure database management system and enhancive database security system. According to the view of enhancive database security system, this paper takes the typical TCSEC model as reference. An agent system is built between database client and database server for secure communication, SQL parsing and access controlling.

目前，我国数据库安全技术研究主要有安全数据库管理系统和数据库安全增强系统两个方向，本文主要从数据库安全增强系统的角度出发，参考经典的TCSEC监视器模型，在数据库客户端和服务器端之间建立一个代理系统，来完成数据库的安全通信、SQL分析和访问控制等功能。

By reusing existing security associations, a mobile unit can begin secure communications immediately following the hand-over.

通过重新使用现有的安全关联，移动单元在切换之后能立即开始进行安全通信。

In the research of secure communication, the thesis analyzes some shortcomings of Diffie - Hellman"s crypt key exchanging protocol, presenting a new exchanging method based on the "station to station protocol and cookie mechanism, realizing the software of crypt key exchanging and secure communication of IP datagram on router.

在对安全通信的研究中，本文分析了Diffie-Hellman密钥交换协议中易受攻击的地方，提出了基于端对端协议及cookie机制的密钥交换新方法，并在路由器上实现了密钥交换和IP报文的安全通信。

Chaotic encryption applies a new research approach to solve security of information in computer network and security communication inaugurate.

混沌加密在计算机网络和安全通信方面的应用为解决信息安全问题开辟了一种新的研究途径。

Firstly, this paper puts forward an improved authentication and key distribution scheme for internet environment, in which we adhibit multilevel authentication center, encryption technology of DES, RSA and one-way function to actualize the safety of communication among the different user on network and reduces the workload of the authentication institution; at the same time, this scheme can also assure the security of network. Besides, it use the temporary symbol and the responds" sign of both-side correspondent to replace time stamp and applies them to internet communication to countercheck "rebroadcast attack and accordingly resolves the problem that it needs synchronization for network clock.

本文在首先提出一种改进的Internet网络环境下的认证及密钥分配方案，该方案考虑采用了多级认证中心，DES、RSA和单向函数加密机制，实现了网络上不同用户间的安全通信，降低了网上认证机构的工作量，同时也能够保证网络的安全性；并用通信双方的临时标志和响应者标识来代替时间戳应用于Internet通信中以防止&重播&攻击，从而解决了以往需要网络时钟同步这一难题。

The data mapping modulation, by which the information data are mapped as the combinatorial sequence, and the security protocol method of the parallel combinatory SS communication system are presented in this paper.

本文提出了并行组合扩频通信的数据调制映射法，并以此为基础，给出了一种安全通信协议方式，既可作身份认证又有好的保密能力。

The systems include application sub-system and cretification authority, application sub-system apply symmetric and asymmetric cryptosystem and public-key certificate which was authoticated by CA and can certify the valid user-identity to set up secure communication channel, exchange session key and provide message integrity, confidetiality, authentication and nondeniability.

系统包括证书中心和应用子系统，证书中心签发证书用来证明用户的合法身份，应用子系统应用证书和对称、非对称密码体制，识别用户合法身份，建立了安全通信通道和交换会话密钥，实现了通信数据的完整性、保密性、真实性、不可否认性。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。