A secure communication system for classified documents over public network

This paper proposes an information system for the transfer of classified document between users in military and governmental organisations, based on Bell-La Padula security model. Governmental and military documents contain information with different level of sensitivity, which has to be shared by user communities and managed according to access control policies. In the proposed system we achieve security using XML security standards for protection of document, Bell-La Padula security model to assure the access control to the documents and symmetrical encryption algorithm to protect communication over public network. Also, is very important in this kind of organisation to assure non-repudiation, integrity, confidentiality and access control of the document.