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Role-based access control (RBAC) models have generated a great interest in the security community as a powerful and generalized approach to security management. In many practical scenarios, users may be restricted to assume roles only at predefined time periods. Furthermore, roles may only be invoked on prespecified intervals of time depending upon when(More)
Multimedia computer systems are required to store, retrieve, and communicate objects comprised of mixed data types including images, text and voice. An important aspect of multimedia systems is the integration of elements retrieved from databases distributed across a network. Integration of object components requires consideration of the temporal(More)
Multidomain application environments where distributed multiple organizations interoperate with each other are becoming a reality as witnessed by emerging Internet-based enterprise applications. Composition of a global coherent security policy that governs information and resource accesses in such environments is a challenging problem. In this paper, we(More)
The rapid proliferation of the Internet and the cost-effective growth of its key enabling technologies are revolutionizing information technology and creating unprecedented opportunities for developing largescale distributed applications. At the same time, there is a growing concern over the security of Web-based applications, which are rapidly being(More)
Proving ownership rights on outsourced relational databases is a crucial issue in today's internet-based application environments and in many content distribution applications. In this paper, we present a mechanism for proof of ownership based on the secure embedding of a robust imperceptible watermark in relational data. We formulate the watermarking of(More)
The XML role-based access control (X-RBAC) specification language addresses multidomain environments' policy-specification needs. X-RBAC is based on an extension of the widely accepted US National Institute of Standards and Technology role-based access-control (RBAC) model. In addition to allowing specification of RBAC policies and facilitating(More)
Synchronization of multiple data streams in time has been recognized as a significant requirement of future multimedia applications utilizing broadband communication technology. Although this requirement has been approached for such single channel media as packetized audio and video, a general solution has not been identified for the provision of(More)
Multimedia data often have time dependencies that must be satisfied at presentation time. To support a general-purpose multimedia information system, these timing relationships must be managed to provide utility to both the data presentation system and the multimedia author. In this paper we propose new conceptual models for capturing these timing(More)
A key challenge in Web services security is the design of effective access control schemes that can adequately meet the unique security challenges posed by the Web services paradigm. Despite the recent advances in Web based access control approaches applicable to Web services, there remain issues that impede the development of effective access control(More)
Modern day enterprises exhibit a growing trend toward adoption of enterprise computing services for efficient resource utilization, scalability, and flexibility. These environments are characterized by heterogeneous, distributed computing systems exchanging enormous volumes of time-critical data with varying levels of access control in a dynamic business(More)