In this chapter, we present the main security issues related to the selective dissemination of information (SDI system). More precisely, after provided an overview of the work carried out in this field, we have focused on the security properties that a secure SDI system (SSDI system) must satisfy and on some of the strategies and mechanisms that can be used to ensure them. Indeed, since XML is the today emerging standard for data exchange over the Web, we have casted our attention on Secure and Selective XML data dissemination (SSXD). As a result, we have presented a SSXD system providing a comprehensive solution to XML documents. In the proposed chapter, we also consider innovative architecture for the data dissemination, by suggesting a SSXD system exploiting the third-party architecture, since this architecture is receiving growing attention as a new paradigm for data dissemination over the web. In a third-party architecture, there is a distinction between the Owner and the Publisher of information. The Owner is the producer of the information, whereas Publishers are responsible for managing (a portion of) the Owner information and for answering user queries. A relevant issue in this architecture is how the Owner can ensure a secure dissemination of its data, even if the data are managed by a third-party. Such scenario requires a redefinition of dissemination mechanisms developed for the traditional SSXD system. Indeed, the traditional techniques cannot be exploited in a third party scenario. For instance, let us consider the traditional digital signature techniques, used to ensure data integrity and authenticity. In a third party scenario, that is, a scenario where a third party may prune some of the nodes of the original document based on user queries, the traditional digital signature is not applicable, since its correctness is based on the requirement that the signing and verification process are performed on exactly the same bits.
Medicare coding and reimbursement for clinical laboratory services
