A Multisignature-Based Secure and OBU-Friendly Emergency Reporting Scheme in VANET

Acting as an important part of Internet of Things (IoTs), vehicular ad-hoc network (VANET) has attracted considerable attention in recent years, where the emergency reporting system is a significant branch and can improve road safety and optimize traffic management. In an emergency reporting system, the authenticity of the emergency messages needs to be ensured carefully since malicious entities may report fake emergency messages to seek personal profit. However, most existing emergency reporting schemes are not efficient enough for secure reporting, given the limited resources of onboard units (OBUs). In this work, we propose a new emergency reporting architecture based on multisignature, where the computation and communication overhead of road-side units (RSUs) is greatly reduced, as the signatures sent to the RSUs have been aggregated. Then, we transform a chameleon signature into a multisignature and propose a secure and OBU-friendly emergency reporting scheme (SOERS) under our architecture. The proposed scheme only requires one hash, two multiplication, and two addition operations to generate a signature for each OBU. Moreover, batch verification of multisignatures further improves the efficiency. Security analysis shows that our scheme is secure against the vehicles-collusion attack and the rogue-key attack, which is a severe issue in multisignature. Finally, performance evaluation shows that our scheme is an efficient solution for emergency reporting.