Studies on Contact Avoidace Routing in Delay Tolerant Networks
Naoki Uchida · Institutional Repositories DataBase (IRDB)
Delay tolerant networks (DTNs) are widely adopted in communication applications in areas where cellular networks are unavailable, such as disaster recovery sites.In such critical network environments, defense mechanisms against contactbased attacks are essential.These attacks include scenarios where a legitimate message carrier is coerced by an adversary upon contact, leading to the leakage of confidential information.Our research group has proposed the contact avoidance routing (CAR) protocol as a secure routing protocol against contact-based attacks in DTNs.CAR determines whether a message holder should forward the message to another carrier in the network by evaluating the probability that the message can be safely delivered to the destination before the message deadline.In this paper, we extend CAR and propose three protocols that enable more secure and efficient message transmission with significantly lower computational costs.First, to improve the efficiency and accuracy of estimating the message delivery probability calculated using the phase-type distribution in CAR, we propose a random sampling CAR (RSCAR).Instead of evaluating all possible paths to the destination, RSCAR estimates the delivery probability by accumulating evaluations of a randomly selected finite set of paths.Next, to adapt to network environments where the overall contact frequency between carriers is low, we propose an adaptive RSCAR (A-RSCAR), which dynamically adjusts the number of hops considered for path exploration.Finally, to achieve a higher success rate of secure message transmission, we propose a secret sharing-base RSCAR (SS-RSCAR), which employs the secret sharing scheme to divide the message into multiple share messages and transmit them along different paths.Simulations using mobile terminal contact trace data and randomly generated network graphs demonstrate that the proposed method provides more secure message transmission with lower computational costs than existing methods.