Security concepts and implementation in the Ara mobile agent system

We describe the security architecture of the Ara mobile agent platform, after reviewing the relevant aspects of comparable systems. The Ara model features few principals, a simple authentication and encryption API, and a simple but highly customizable authorization scheme. One system may contain many virtual places, each establishing a domain of logically related services under a common security policy governing all agents at this place. Agents are equipped with allowances limiting their resource accesses, both globally per agent lifetime and locally per place. Various aspects of the implementation of this model are discussed, and finally the situation and limitations of Ara and other systems are summarized.