中文摘要：

XML数据库的关键字检索简单易用,并且用户不必了解数据库的模式,近期受到人们的广泛关注。当前的相关研究主要集中于关键字检索的算法以及返回结果的组织和排序,然而却忽视了关键字的安全访问控制问题。结合XML关键字搜索和XML安全访问控制,提出一种新的建立于XML Schema上基于角色的访问控制规则SRACP（Schema Role Access Control Policy）,并在SRACP规则的基础上建立安全的XML关键字检索的索引（SRACP-Index）,包括：SRACP-Index的数据结构,SRACP-Index的构建和算法,以及如何利用SRACP-Index的建立进行SSLCA的查询。最后通过实验证明该索引和SSLCA查询算法的有效性。

英文摘要：

Keyword search of XML database is simple and easy to use,and the users do not have to understand the pattern of the database.Recently it is widely concerned by the people.Current researches on this issue mainly focus on the algorithms of the keyword search and the organisation and sorting of the returned results,but the issue of secure access control of the keywords is ignored.Combining XML keyword search and XML secure access control,in this paper we put forward a new Role-based Access Control Policy which is built based on XML Schema（SRACP）,and on the basis of SRACP,we built a secure index for XML keyword search（SRACP-Index） including the data structure of the SRACP-Index,the construction and algorithm of the SRACP-Index,and the way to carry out SSLCA search using the SRACP-Index.At the end,we proved the validity of our index and SSLCA search algorithm through experiments.