Classified XML Documents Protection Scheme

With the expanding of XML applications, more and more data are expressed, exchanged, strored and retrieved in XML data format. Large amount of XML data are stored in computer system, transported and switched through network. Once some confidential information are stealed or deleted illegally, it will lead to incalculable losses.Therefore, an effective way for protecting classified documents is to build a multi-level security system, which is used to control the access right of classified documents.Firstly, this article studies the XML technology and the XML Security which contains XML Encryption, XML Signature and XML Key Management.Secondly, it introduces several access control technologies which are used in the XML multi-level security model currently. The character of the XML multi-level security model is that the classified XML documents are protected through combining multiple access control technologies. Thirdly, a specific multi-level security model is proposed for XML documents. The realization of this model is based on the Chinese Remainder Theorem, which by choosing appropriate parameters and encryption keys to generate the lable of the XML document. Then we let the selected parameters and XML encryption technology combined to realize protection in an XML document. At last, a specific instance of XML document is proposed to verify the validity of the method.