Anonymous authentication mechanism based on group signature and pseudonym public key infrastructure for safety application of vechicular ad hoc network
Safety applications of Vehicular Ad hoc Network (VANET) demand delay intolerant and are vulnerable to attacks due to the mobility of nodes and wireless nature of their communications. These applications require an integrated security mechanism, which provides message integrity, anonymity, non-repudiation, revocation, availability, and location authentication services. This mechanism should provide acceptable message delay with or without dependency to Road Side Units (RSUs). Realizing the importance of VANET security, two mechanisms are proposed and evaluated in this research. The mechanisms are aimed at fulfilling the VANET security requirements for safety applications with acceptable message delay. Two new lightweight security mechanisms, RSU-Aided Anonymous Authentication (RAAA) and Group Signature-based Anonymous Authentication (GSAA) have been proposed. These mechanisms are based on Group Signature (GS) and Pseudonym Public Key Infrastructure (PPKI). GS scheme was applied to ensure anonymity, non-repudiation and revocation, whereas PPKI was applied to achieve authentication and message integrity. Additionally, a novel function for location verification was proposed to guarantee availability and location authentication. Simulations were performed using NS2 to verify and evaluate the efficiency of the mechanisms for urban and highway scenarios with various traffic conditions. Simulation results showed that RAAA and GSAA outperformed Group Signature and Identity-based Signature (GSIS), and Short-Term Linkable Group Signatures with Categorized Batch Verification (STLGSCBV). In comparison to GSIS and STLGSCBV, the results indicated improvements of at least 5.26% and 7.95% in terms of vehicle density impact on message delay, and at least 11.65% and 11.22% in the case of vehicle density impact on message loss ratio. Furthermore, the simulated RAAA and GSAA methods resulted in approximately 11.09% and 10.71% improvement in message delay during signature verification in comparison to GSIS and STLGSCBV. Additionally, RAAA and GSAA proved to achieve at least 13.44% enhancement by considering signature verification on message loss ratio in comparison to GSIS and 7.59% in comparison to STLGSCBV. The simulation results also demonstrated that less than 20ms message delay was achieved by RAAA and GSAA mechanisms in the case of less than 90 vehicles within the communication range. This is an acceptable message delay and hence, the proposed mechanisms have a great potential to be used in safety critical applications
