LoWVR: Low Overhead Watermark based Vehicle Revocation Scheme in VANET

Background and Objective: The inter-vehicle communication is a potential issue for improving road safety, detecting traffic accidents, etc. in vehicular ad hoc network. The communication among the vehicles in VANET must be protected from the dissemination of message by unauthorized vehicles and the alteration of the message by misbehaving vehicles. Methods: In this paper, a low overhead digital watermark based vehicle revocation scheme is proposed. The sender vehicle generates a message and a random number after observing an event. It generates a deformed version of the generated message and message digest, and concatenates them. The watermark bits are generated by the sender vehicle from its unique identification and the random number. The sender vehicle embeds the watermark bits in the concatenated form of the message digest and deformed version of the generated message, and broadcasts the embedded message for its neighbours. The neighbour vehicles extract the required information from the received embedded message to verify the authentication of the sender vehicle and to identify whether the sender vehicle is an alteration attacker. It revokes unauthentic vehicles and vehicles that are identified as alteration attacker from vehicular ad-hoc network without any dependency on the trusted third party. The cracking probability and cracking time are used to measure the robustness of the scheme. The cracking probability and cracking time are measured to set the design guideline regarding the size of the watermark. The qualitative performance of the scheme is measured in terms of storage, communication and computation overhead. The significant reduction of all such overheads is observed by comparing the qualitative performance of the proposed scheme with two existing schemes. Conclusion and Results: Thus, the proposed scheme is a low overhead solution of securing vehicular ad hoc network. Performance of the scheme is also studied quantitatively in terms of the time of verifying vehicle authentication at the receiving end, delay in message dissemination at the sending end and delay in message reception at the receiving end. The quantitative performance is also compared with two of the existing schemes.