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–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)
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)
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 large-scale distributed applications. At the same time, there is a growing concern over the security of Web-based applications , which are rapidly being(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)
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)
— Sensor networks are designed with the assumption that nodes are willing to collaborate. However, the open collaboration of nodes introduces privacy and security issues. Therefore, ensuring privacy in wireless sensor networks is a challenging task. Based on a multilevel security paradigm, in this paper we present a hierarchical key generation and(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)
A Generalized Temporal Role Based Access Control (GTRBAC) model that allows specification of a comprehensive set of temporal constraint for access control has recently been proposed. The model constructs allow one to specify various temporal constraints on role, user-role assignments and role-permission assignments. However, Temporal constraints on role(More)
As the demand for multimedia information systems increases and network technology provides the capability to handle multimedia data, effective communication and synchronization mechanisms are needed in a distributed environment to realize the successful retrieval , composition and presentation of multimedia objects. In this paper, we propose a specification(More)