A Communication-Efficient Secure Routing Protocol for IoT Networks †

This paper proposes a secure routing protocol based on an ad hoc on-demand distance vector to simultaneously achieve communication efficiency and security. Many studies have discussed secure protocols. However, conventional protocols tend to exhibit low communication efficiencies owing to the long packets required by digital signatures, specifically in large-scale networks. Hence, our proposed method aims to allow the intermediate node to initiate a route reply (RREP), which is prohibited in conventional protocols because of digital signature restrictions. Based on an ID-based signature, the proposed protocol allows each intermediate node to hold a packet received from a specific node in the past. Each node then appends it to the route request of another node and generates its own signed RREP. This procedure guarantees that a third party holds the route to the destination. Theoretical evaluations demonstrate that the proposed method outperforms the communication efficiency of conventional secure protocols. We measured the time required for routing (i.e., the sum of communication and cryptographic calculation times) using a Raspberry Pi with C language. We show that the proposed protocol can improve the average routing time by more than 3× compared with conventional methods when 30 relay nodes are randomly distributed in a 300-square meter area.