【作者】 杨勇；

【导师】 周安民；

【作者基本信息】 四川大学 ， 通信与信息系统， 2005， 硕士

【摘要】 数据库技术自20世纪60年代中期产生至今,已得到快速发展和广泛应用。随着计算机技术特别是网络技术的发展,以及电子商务、电子政务的不断发展,数据库的应用产生了许多新的发展趋势。有相当多的组织、企业由于受到经济、技术等的限制,不可能去购买昂贵的硬件和软件去组建自己的数据库服务系统,同时也没有足够的能力去克服数据维护、软件升级等带来的不便,那么在网络环境下,如何建立一套实用的、专业的数据库服务系统来满足这些组织、企业的这种需要?而提供这种服务的服务商又应采用什么样的机制来为用户提供对数据的产生、存储和访问,以及如何有效地保证其中的数据安全性,就成为迫切需要研究的课题。 针对这一迫切需要,借鉴ASP(Application Service Provider)的发展模式,本文首先提出了数据库服务提供(DSP:Database Service Provider)模型这一概念,并对DSP模型的结构作为分析和研究,建立了一套实用的DSP应用模型,作为本文以后研究、实现的基础。 在DSP模型中,存储于服务商处的数据对于用户而言,是很重要,也很有价值的财产,其最重要的要求在于:数据的私密性。用户会认为服务商是不完全可信的,从而不希望其它任何人,尤其是具有很高权限的服务提供商的DBA(数据库管理员)非法窃取自己的数据。其次是系统的有效性。由于在网络环境中,用户和服务商主机又可能处于不同的地点,甚至是不同的媒介上,用户对自己数据的访问是会有效率要求的,而且很明显,这种要求也很重要。 加密技术对数据库中存储的高度敏感机密性数据,起着越来越重要的作用,是防止数据库中的数据在存储和传输中失密的有效手段,所以完全可以用于DSP模型。但目前的数据库加密手段都存在着以下不足:一是加密后,SOL语言不能直接在加密数据上进行操作。传统的做法是在服务器端全部解密,再进行相应的查询,这除了将增加服务器的负荷外,还将给这些敏感信息带来安全性上的问题,包括在服务器上和在传输通道上;二是数据加密后,为了减少服务器的负荷,将所要求的密文全部下到客户端进行解密,再进行相应的SOL查询,这将给通信网络带来过大的负荷,造成效率更多还原

【Abstract】 From appearance of the Database’s technology on 1960s to now, it has been developed and applied rapidly and widely. With the development of computer technology, e-commerce and e-government, especially the Internet, the Database grows a lot of new applied trends. Because of the limitations such as economy, technology etc, many organizations and enterprises have no ability to chase the expensive hardware and software to build their own Database service system as well as they aren’t able to overcome the troubles caused by the maintaining data and upgrading software. Therefore, how to build a suit of available and professional database service system in order to resolve their problems. And which mechanism applied by service provider can provide the users to produce data, save data and access data and efficiently protect the data’s security. These problems are necessary to be researched.So in this paper, we, utilizing the application service provider model, firstly present the concept of database service provider model. Secondly, we analyze and research the structure of DSP model and build an available DSP model for our further research.In DSP model, the data lying in provider is very important and valuable for the data’s owner. So the most important request is the data’s privacy. The owners consider the provider is unconfident. And hope anyone, especially the high-privilege DBA(database administrator) of provider, can not steals their data. The other request is the system efficiency. In Internet, the owner’s host and the provider’s host lie in different place and even different media. So the owners are bound to request the access efficiency. Apparently, this request is very important, too.The encryption plays more and more important roles for the high sensitive and confidential data in database. And the encryption is one of useful ways to protect the data in database from being stolen during saving and transmitting. Therefore, the encryption can be used in DSP model. But the current database encryption has the following faults:Firstly, the SQL cannot directly be operated on the encrypted data. The conventional method is that the queries are be operated on server after the data be unencrypted. But this way not only adds the server’s load but also brings some secure problems on server and transmitting path.Secondly, in order to reduce the server’s load, the SQL can be operated after the encrypted data are transmitted from server to client and are unencrypted on client. This way can make the network jam so that there is very low efficiency.As a result, on the basis of DSP model structure, we work out and deeply research a kind of new method that can directly research or query on encrypted data so that we can effectively protect the data privacy and guarantee efficiency in DSP. And according to the results of the research, we realize the encryption in DSP. At the same time, these results can be applied not only to database, but also to the saving encrypted data, accessing encrypted data and confidentiality of other fields, such as the secure protection of logs, the secure protection of e-mail, and so on.更多还原