Abstract
Unlike the conventional routing techniques in Internet where routing privileges are given to trustworthy and fully authenticated nodes, delay-tolerant networks (DTNs) allow any node to participate in routing due to the lack of consistent infrastructure and central administration. This creates new security issues since even authorized nodes in DTNs could inject several malicious threats into the network. This paper investigates the problem of mitigating blackhole attacks in DTNs based on the Spray-and-Wait routing protocol. A new knowledge-based routing scheme, called Trust-Based Spray-and-Wait protocol (TB-SnW), is designed based on distributed trust management. Each node maintains the trust levels for encountered nodes based on the message exchange history, and uses the trust levels to smartly distribute message copies to bypass blackhole attackers. Simulation results demonstrate that, compared with Spray-and-Wait, TB-SnW can achieve higher message delivery rate with very low communication overhead in DTNs that suffer from blackhole attacks.