Attribute-based authentication for multi-agent systems with dynamic groups

In a multi-agent system, agents are required to interact in order to exchange information. To achieve a reliable information exchange, a sound security protection must be in place. Unfortunately, security and privacy in multi-agent systems have not drawn adequate attention. They have been actually ignored or mistreated in most proposed multi-agent protocols. We observe that security and privacy issues are indeed not trivial and cannot be resolved with traditional security mechanisms, if agents are not trusted each other and their privacy must be protected. In this paper, we propose a secure multi-agent protocol that captures several most important security properties including agent privacy, data confidentiality, and agent authenticity. Intuitionally, we allow each agent in a group to hold a set of policy attributes. To access a protected data set, an agent must hold a correct policy attribute. In other words, the private information between two agents can be exchanged, if and only if the policy attribute embedded in the transmitted message matches that held by the receiver. In case of mismatching attributes, the private information of the corresponding agent will not be revealed to their counterpart. The proposed scheme is formalized with a sound cryptographic algorithm with a rigorous security proof.