for security and privacy is paramount to the success of

Trust is an integral component in many kinds of human interaction, allowing people to act under uncertainty and with the risk of negative consequences. For example, exchanging money for a service, giving access to your property, and choosing between conflicting sources of information all may utilize some form of trust. In computer science, trust is a widelyused term whose definition differs among researchers and application areas. Trust is an essential component of the vision for the Semantic Web, where both new problems and new applications of trust are being studied. This paper gives an overview of existing trust research in computer science and the Semantic Web.

Because ever more powerful intelligent agents will interact with people in increasingly sophisticated and important ways, greater attention must be given to the technical and social aspects of how to make agents acceptable to people [87]. The technical challenge is to devise a computational structure that guarantees that from

This paper summarizes our efforts to develop capabilities for policy and contract management for Semantic Web Services applications. KAoS services and tools allow for the specification, management, analyzes, disclosure and enforcement of policies represented in OWL. We discuss three current Semantic Web Services applications as examples of the kinds of roles that a policy management framework can play: as an authorization service in grid computing environments, as a distributed policy specification and enforcement capability for a semantic matchmaker, and as a verification tool for services composition and contract management.

Traditional security policies largely focus on access control requirements, which specify who can access what under what circumstances. Besides access control requirements, the availability of services in many applications often further imposes obligation requirements, which specify what actions have to be taken by a subject in the future as a condition of getting certain privileges at present. However, it is not clear yet what the implications of obligation policies are concerning the security goals of a system. In this paper, we propose a formal metamodel that captures the key aspects of a system that are relevant to obligation management. We formally investigate the interpretation of security policies from the perspective of obligations, and define secure system states based on the concept of accountability. We also study the complexity of checking a state’s accountability under different assumptions about a system.

Policy Based Management (PBM) is a research topic that has been driven by the tremendous complexity inherent in the administration and management of present-day networking and telecommunications systems and services. The increasingly diverse organisational forms of modern industry represent a significant component of this complexity. Internet communities offer extreme examples of organisational diversity, since they often lack any central authority and many subsections operate with almost complete autonomy. This paper argues that PBM systems offer great potential in this domain due to the complexity of management arrangements. However, since these communities lack any single trusted administrative hierarchy, a centralised solution to policy engineering and management is not possible. This paper proposes an approach to modelling communities for PBM systems. This approach focuses on the concept of communities within a hierarchy of authority as the fundamental unit of organisational analysis. As such, the model reflects the distribution of authority in the real-world community, the resulting policies reflect the community's operational needs and contracts between the various groups and individuals that make up the community. Policy conflicts are used to identify organisational conflicts that must be resolved. In order to illustrate and validate these concepts, the paper presents a conceptual architecture and case study based on the secure management of an open publishing network. 1.

Abstract. Several research groups have grappled with the problem of characterizing and developing practical approaches for implementing adjustable autonomy and mixed-initiative interaction in deployed systems. However, each group takes a little different approach and uses variations of the same terminology in a somewhat different fashion. In this chapter, we will describe some common dimensions in order to better understand these important but ill-characterized topics. We will also sketch the approach to implementation we are developing in the context of our research on policygoverned autonomous systems. 1

In this paper we describe our experience in applying KAoS services to ensure policy compliance for Semantic Web Services workflow composition and enactment. We are developing these capabilities within the context of two applications: Coalition Search and Rescue (CoSAR-TS) and Semantic Firewall (SFW). We describe how this work has uncovered requirements for increasing the expressivity of policy beyond what can be done with description logic (e.g., role-value-maps), and how we are extending our representation and reasoning mechanisms in a carefully controlled manner to that end. Since KAoS employs OWL for policy representation, it fits naturally with the use of OWL-S workflow descriptions generated by the AIAI I-X planning system in the CoSAR-TS application. The advanced reasoning mechanisms of KAoS are based on the JTP inference engine and enable the analysis of classes and instances of processes from a policy perspective. As the result of analysis, KAoS concludes whether a particular workflow step is allowed by policy and whether the performance of this step would incur additional policy-generated obligations. Issues in the representation of processes within OWL-S are described. Besides what is done during workflow composition, aspects of policy compliance can be checked at runtime when a workflow is enacted. We illustrate these capabilities through two application examples. Finally, we outline plans for future work. 1.

In this paper, we present a novel policy middleware architecture for managing IT systems and applications that span multiple networks and administrative domains. The proposed policy middleware provides a standard infrastructure for the creation, storage, distribution, and execution of policies, and helps in reducing the cost of making IT systems policyaware. In particular, we focus on three aspects of the proposed policy middleware that help in making the middleware fully general: (1) a platform-neutral and extensible specification of policies; (2) the local ratification of policies, which lets system administrators accept, reject, or flag an incoming policy; and (3) the transformation of policies, which allows system administrators to transform incoming policies to match their local environment. We present our experience in building an application on the proposed middleware to audit the configuration of a storage area network. We also present performance results from a prototype and show that our policy middleware design can scale to handle a large number of policies. 1.

Summary. The Semantic Web aims at enabling sophisticated and autonomic machine to machine interactions without human intervention, by providing machines not only with data but also with its meaning (semantics). In this setting, traditional security mechanisms are not suitable anymore. For example, identity-based access control assumes that parties are known in advance. Then, a machine first determines the identity of the requester in order to either grant or deny access, depending on its associated information (e.g., by looking up its set of permissions). In the Semantic Web, any two strangers can interact with each other automatically and therefore this assumption does not hold. Hence, a semantically enriched process is required in order to regulate an automatic access to sensitive information. Policy-based access control provides sophisticated means in order to support protecting sensitive resources and information disclosure. However, the term policy is often overloaded. A general definition might be “a statement that defines the behaviour of a system”. However, such a general definition encompasses different notions, including security policies, trust management