A Nested Token-Based Delegation Scheme for Cascaded Delegation in Mobile Agent Environments

In mobile agent environments, cascaded delegation occurs frequently among places due to the mobility of agents. Because the existing scheme considers only the delegation between two places which participate in migration of an agent, it is inadequate in the situation that needs cascaded delegation. In this paper, we propose a delegation scheme that provides agents with secure cascaded delegation. The proposed scheme achieves the goal by nesting each delegation token 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.