Practical security for disconnected nodes

Endpoints in a delay tolerant network (DTN) [K. Fall, 2003] must deal with long periods of disconnection, large end-to-end communication delays, and opportunistic communication over intermittent links. This makes traditional security mechanisms inefficient and sometimes unsuitable. We study three specific problems that arise naturally in this context: initiation of a secure channel by a disconnected user using an opportunistic connection, mutual authentication over an opportunistic link, and protection of disconnected users from attacks initiated by compromised identities. We propose a security architecture for DTN based on hierarchical identity based cryptography (HIBC) that provides efficient and practical solutions to these problems.