The paper proposes an approach to content dissemination that exploits the structural properties of XML Document Object Model in order to provide efficient dissemination by at the same time assuring content integrity and confidentiality. Our approach is based on the notion of encrypted post-order numbers that support the integrity and confidentiality requirements of XML content as well as facilitate efficient identification, extraction and distribution of selected content portions. By using such notion, we develop a structure-based routing scheme that prevents information leaks in XML-data dissemination and assures that content is delivered to users according to the access control policies, that is, policies specifying which users can receive which portions of the contents. Our proposed dissemination approach further enhances such structure-based, policy-based routing by combining it with multicast in order to provide high efficiency in terms of bandwidth usage and speed of data delivery, thereby enhancing scalability.