Protecting the computation results of free-roaming agents

When mobile agents do comparison shopping for their owners, they are subject to attacks of malicious hosts executing the agents. We present a family of protocols that protect the computation results established by free-roaming mobile agents. Our protocols enable the owner of the agent to detect upon its return whether a visited host has maliciously altered the state of the agent, thus providing forward integrity and truncation resilience. In an environment without public-key infrastructure, the protocols are based only on a secret hash chain. With a public-key infrastructure, the protocols also guarantee non-repudiability. © 1998 Springer-Verlag London Ltd.