多数据库系统安全性研究-智能与分布计算实验室

多数据库系统安全性研究

姓名	陈帆
论文答辩日期	2004.05.10
论文提交日期	2004.05.11
论文级别	硕士
中文题名	多数据库系统安全性研究
英文题名	security in multidatabase system
导师1	卢正鼎
导师2
中文关键词	多数据库系统;通信安全;用户认证;访问控制;数字证书
英文关键词	multidatabase system;communication security;user authentication;access control;digital certificate
中文文摘	网络技术和数据库技术，构成了多数据库系统的基础。多数据库很好地解决了在已存的、异构的、分布的多个局部数据库系统之间共享和集成数据的问题。随着对系统安全的愈发重视，向多数据库系统中加入安全模块成为一项迫切需要的工作。由于多数据库的分布性、自治性和异构性，使得多数据库系统的安全机制和传统数据库有较大不同。多数据库系统处于分布式网络环境中，为保证各个组成部分之间的通信安全，设计了一个基于数字证书体系结构的多数据库安全系统模型。通过在通信开始之前确认证书有效性并且建立保密通道，实现了多数据库系统中各分布式服务器和客户端的安全连接，保证了通信过程的安全。多数据库系统中的用户分为全局用户和局部用户，可以分别由多数据库全局管理员和局部数据库管理员自行管理。用户以全局用户的身份访问多数据库系统，以局部用户的身份访问局部数据库。分析了几种在全局用户与局部用户之间进行映射的用户认证方法来鉴别多数据库系统中的用户。在研究了多数据库系统的访问控制实体和访问规则等问题的基础之上，设计了一个多数据库角色权限分配模型，能够在较好保持系统自治性和异构性的同时，实现访问权限的管理。基于上述理论，设计了具有安全模块的Panorama多数据库原型系统。该系统采用X.509数字证书和加密套接字协议层（SSL）技术，成功地实现了CORBA架构下的通信安全。依靠数字证书带来的加密功能，采用权限分配请求分发方式，用加密的XML文件在多数据库系统中实现了较为灵活全局用户到局部用户的映射，并由此实施了访问控制。
英文文摘	A multidatabase system (MDBS), based on network and database technologies, is a system that supports data sharing and integrating of a collection of pre-existing, heterogeneous, distributed local database systems. Adding a security module into MDBS is urgent when more and more system security problems come into notice. Because of the heterogeneity, distribution and autonomy of MDBS, the security mechanism in MDBS is much different to that in traditional database. A MDBS security model based on digital certificate is designed in this paper to ensure the secret communication among the components in the distributed network. With verifying the digital certificates and establishing the secret connections, safe communications between the servers and clients in MDBS are kept. There are two kinds of users in MDBS: global user and local user, which can be managed by the corresponding managers independently. We enter the MDBS as a global user, and access into the local data source as a local user. Some methods to identify users in MDBS, divided by the different ways to map between global users and local users, are analyzed. Based on the analysis of the theories about access entities and access roles, a role privilege assignment model is proposed in order to realize access control and preserve the heterogeneity and autonomy in MDBS, According to the ideas above, we add a security module into Panorama, a multidatabase prototype system. X.509 digital certificate and Security Socket Layer (SSL) are introduced into Panorama, and communication security under Common Object Request Broker Architecture (CORBA) is realized. By the benefit of digital certificate, the privilege assignment request could be distributed by encrypted XML format. In this way, the global users could be mapped to the local users more flexibly and access control could be implemented.