Realization of authentication and integrated protection of PDF documents based on XML

PDF documents have become the universal document format transferred on line,but their authentication and integrated protection is still a problem because the common image authentication and integrated protection technique is no use in PDF documents.XML is applied in describing file structures and contents.The operations of content-extracting,data-mining and information-filtering were completely transferred from PDF documents to XML documents.The authentication and integrated protection of PDF documents were realised.