Reliable cascaded delegation scheme for mobile agent environments

In mobile agent environments, migration of an agent occurs continuously due to the mobility of the agent. So, cascaded delegation can occur among places for delegating the privilege to execute the agent. Because the existing delegation scheme considers only the delegation between two places that participate in migration of an agent, it does not support secure cascaded delegation. In this paper, we propose a cascaded delegation scheme that provides agents with secure cascaded delegation in mobile agent environments. Depending on the trust-relationship among places, the proposed scheme achieves the goal by nesting each delegation token or by nesting only initial token signed by sender of the agent within the signed part of the next immediate delegation token. We prove that the proposed scheme is secure against the attack of replaying a message and the attack of substituting a delegation token.