Reinier J. Timmer

Enforcing security in the AgentScape middleware

Multi Agent Systems (MAS) provide a useful paradigm for accessing distributed resources in an autonomic and self-directed manner. Resources, such as web services, are increasingly becoming available in large distributed environments. Currently, numerous multi agent systems are available. However, for the multi agent paradigm to become a genuine mainstream success certain key features need to be addressed: the foremost being security. While security has been a focus of the MAS community, configuring and managing such multi agent systems typically remains non-trivial. Well defined and easily configurable security policies address this issue. A security architecture that is both flexible and featureful is prerequisite for a MAS. A novel security policy enforcement system for multi agent middleware systems is introduced. The system facilitates a set of good default configurations but also allows extensive scope for users to develop customised policies to suit their individual needs. An agent middleware, AgentScape, is used to illustrate the system.

Enforcing integrity of agent migration paths by distribution of trust

Agent mobility is the ability of an agent to migrate from one location to another across a network. Though conceptually relatively straightforward, in practice security of mobile agents is a challenge: from transport layer security to preservation of integrity in open environments. This paper discusses the security issues involved and proposes protocols for secure agent migration. AgentScape, an agent platform for mobile agents, is used to illustrate the feasibility of the implementation of these protocols.

Constructing secure mobile agent systems using the agent operating system

Designing a secure and reliable mobile agent system is a difficult task. The agent operating system (AOS) is a building block that simplifies this task. AOS provides common primitives required by most mobile agent middleware systems, such as primitives for secure communication, secure and tamper-evident agent packaging and agent migration. Different middleware processes can use AOS at the same time; effective security mechanisms protect AOS resources owned by different middleware processes. Designed as a portable and language-neutral middleware layer residing between the mobile agent system and the operating system, AOS facilitates interoperability between agent platforms and between different implementations of AOS itself. AOS has been implemented in both C++ and Java. This paper motivates the design of AOS, describes how AOS is used in a mobile agent system, and presents performance measures for an agent transfer protocol layered upon AOS.

Design of a Secure and Decentralized Location Service for Agent Platforms

Agent platforms designed for Internet-scale, open networks need scalable and secure location services for agents and services. The location service based on the Fonkey public key distribution infrastructure presented in this paper has been designed and implemented for this purpose. It is scalable in the total number of published identifier---contact address pairs, the number of updates/changes, and the number of agent platforms publishing and requesting contact addresses. This system also supports a signing mechanism to authenticate the publisher of an identifier---contact address pair. Experimental results show that the current implementation based on the Bunshin/Free Pastry overlay network exhibits good scaling behavior.

Modelling Multi-stakeholder Systems: A Case Study

A contemporary governance challenge for governments concerns the biogas domain: what incentives and policies can lead to a viable biogas economy? To support addressing this challenge, a prototype of a simulator is constructed in which horizontal governance is applied in a multi-stakeholder context. This paper reports on the modelling and knowledge acquisition that led to the development of that prototype. Rather than (re)inventing tooling, three available agent-based modelling approaches are combined: the MAIA meta-model, OperA and GENIUS, with Agents cape as the agent-based middleware for the realisation of the simulator. The resulting simulator has been validated by biogas experts from Alliander (NL-based energy network company), leading to confirmation that our combined approach was useful for the analysis of this multi-stakeholder domain.

WS-agreement based resource negotiation in AgentScape

Mobile agents require access to computing resources on heterogeneous systems across the Internet. This demo illustrates how agents can negotiate terms and conditions of resource access with one or more mediators representing virtual organizations of autonomous hosts, before migrating to a new location. Time-limited resource contracts are the result: contracts between agents and mediators, and contracts between mediators and hosts. The negotiation protocol and language are based on the WS-Agreement Specification, and have been implemented and tested within the Agent-Scape framework. The demonstration shows in detail how this negotiation framework has been implemented for resource access on remote, distributed systems.

An agent based system for distributed information management: A case study

Securely managing shared information in distributed environments across multiple organizations is a challenge. Distributed information management systems designed to this purpose, must be able to support individual organizationspsila information policies whilst ensuring global consistency and completeness of information. This paper describes a multi-agent based prototype implementation of a distributed information management system, for distributed digital criminal dossiers. The prototype implementation runs on the multi-agent platform AgentScape.