Policy based roles for distributed systems security

Distributed systems are increasingly being used in commercial environments necessitating the development of trustworthy and reliable security mechanisms. There is often no clear informal or formal specification of enterprise authorisation policies and no tools to translate policy specifications to access control implementation mechanisms such as capabilities or Access Control Lists. It is thus difficult to analyse the policy to detect conflicts or flaws and it is difficult to verify that the implementation corresponds to the policy specification. We present in this paper a framework for the specification of management policies. We are concerned with two types of policies: obligations which specify what activities a manager or agent must or must not perform on a set of target objects and authorisations which specify what activities a subject (manager or agent) can or can not perform on the set of target objects. Management policies are then grouped into roles reflecting the organisation..

Dynamic Maintenance of Service Orchestrations

International audienceService-oriented architectures evolved rapidly as the solution to the latest requirements for loosely-coupled distributed computing. Into this broad context several approaches emerged towards the discovery and the systematic composition/orchestration of services. One of the next challenges in this field is the maintenance of service-oriented architectures towards accomplishing the ultimate goal of constructing eternal service-oriented systems out of loosely- coupled basic engineering elements. The particular problem we deal with in this paper is the dynamic maintenance of service orchestrations in the presence of unavailable services. Specifically, we focus on the dynamic substitution of stateful services that become unavailable during the execution of service orchestrations. As an answer to this problem, we propose the SIROCO middleware platform which is further detailed along with an experimental evaluation of our first prototype. Our findings show that SIROCO provides the necessary means for achieving dynamic maintenance with a reasonable expense on the execution of service orchestrations

Policy analysis for DiffServ quality of service management

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Building Reconfiguration Primitives into the Law of a System

Given a certain class C of reconfigurations, deemed to be potentially important for a given system, we define a reconfiguration suite S C to be a set of primitive operations that satisfy the following conditions: ffl Any reconfiguration in C can be carried out by a sequence of primitives from S C . ffl The correctness of S C should be independent of the functionality of the system, and invariant of its reconfigurations (for a given set of possible configurations of the system at hand). We describe a mechanism for implementing such reconfiguration suites, for a system that operates under law-governed interaction (LGI), currently supported by an experimental toolkit called Moses. LGI is a mode of interaction between the members of a given group (or system) of agents, which is governed by an explicit and strictly enforced set of rules, called the law of this group. The existence of such a law under LGI provides us with an architectural model of the system, which can be made to inclu..