Defend mobile agent against malicious hosts in migration itineraries

Agent integrity verification and fault-tolerance are the two prevalent methods among the solutions to the Problem of Malicious Hosts in Mobile agent system. Agent integrity verification enables the owner of the agent to detect upon its return whether a visited host has maliciously altered the state of the agent based on agent integrity verification [6]. A known drawback of such method is that it cannot detect the tampering of agent immediately, and the tampering can be detected only when the agent returned. Agent fault-tolerance is one method that achieves agent fault-tolerance in migration itineraries by agent replication and majority voting [11]. The drawback of such method is that the agent replication and majority voting can produce many agent replicas in every agent migration step, which may cost significant resource and time. Aiming at those drawbacks, the paper incorporates the two methods, and presents a novel agent migration fault-tolerance model based on integrity verification, which can defend mobile agent against malicious hosts in migration itineraries effectively. The novel agent fault-tolerance model cannot only realize the fault-tolerant execution, but also reduce the complexity and resource cost of agent migration communication. q 2004 Elsevier B.V. All rights reserved.