Secure opportunistic routing protocol based on reputation systems in VANETs

Vehicular ad hoc Networks (VANETs) are auto-organised networks that do not rely on any infrastructure or central authority. Nodes are vehicles and roadside Units (RSU), exchange transport-related information to assist in driving safety and infotainment. VANET communications can be categorised into three types, which are Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Hybrid architecture. In this work, we focus on V2V communication (as we simulated a critical safety application which is based on this type of communication) where ad hoc routing protocols are used to establish paths and deliver packets between nodes. There are several routing protocols in VANET, including traditional MANET (Mobile ad hoc networks) routing protocols, but the performances of those protocols decrease in the context of VANET because of the high mobility of nodes that causes frequent changes in the infrastructure and requires quicker updates of paths and routes. Even though routing is a challenging issue, opportunistic routing protocols have been considered as a promising approach for VANETs, as the best route is recalculated at each hop of the path towards the destination and can adapt quickly to topology changes, unlike proactive or reactive routing approaches.

However, VANET routing, as for MANET, relies on the cooperation between nodes to deliver packets between any nodes within the network. But, the selfish behavior of uncooperative nodes can easily be executed (maliciously or unintentionally) and not detected in the absence of authority or adequate routing measures. Thus, routing security and reliability are other important challenges in VANET. Because of the lack of central authority, nodes can misbehave and cause routing issues without being detected. Given the time-critical nature of VANET applications, VANET routing should provide good QoS performances and a trusted reliable path.

In this thesis, we introduce a new trusted opportunistic routing protocol called Trusted Context-aware Opportunistic Routing (TCOR) which provides a secured routing for VANET and it is incorporated with the recommendations (TCORRec). Trusted AODV incorporating recommendation (TAODV-Rec) is a another contribution of this thesis which is implemented and used to compare with the proposed routing protocol.

The proposed protocol has been implemented and simulated under OMNET++. Moreover, to prove the efficiency of TCOR, it has been compared with other routing protocols (COR opportunistic protocol, AODV and trusted AODV). Different metrics and network parameters have been used (nodes mobility and VANET map) to simulate the adequate VANET environment and evaluate the protocols under realistic conditions as much as possible. Results have shown that TCOR and TCOR-Rec outperform traditional routing protocols by approximately 9% and 15% respectively in terms of packet delivery when the network has attacker nodes.