Distributed Security Algorithms for Mobile Agents

Abstract

The use of mobile agents is becoming increasingly popular when computing in networked environments, ranging from Internet to the Data Grid, both as a theoretical computational paradigm and as a system-supported programming platform. In spite of this, mobile agents systems have been largely ignored by the mainstream distributed computing community. It is only recently that several researchers have started to systematically explore this new and exciting distributed computational universe. In this paper we describe some of interesting problems and solution techniques developed in this investigations in the context of security. In fact, at a practical level, in systems supporting mobile agents, security is the most pressing concern, and possibly the most difficult to address. In particular, specific severe security threats are those posed to the network site by harmful agents, and those posed to the mobile agents by harmful hosts. In this chapter we consider security problems of both types; and concentrate on two security problems, one for each type: locating a black hole, and capturing an intruder. For each we discuss the computational issues and the algorithmic techniques and solutions. Although the main focus of this chapter is on security, the topics and the techniques have a much wider theoretical scope and range. The problems themselves are related to long investigated and well established problems in automata theory, computational complexity, and graph theory.