An Efficient Privacy-preserving Authentication Model based on blockchain for VANETs

The existing privacy-preserving authentication models for Vehicular Ad-hoc Networks (VANETs) primarily preserve multiple pseudonyms for one vehicle, while overlooking the consideration of confidential identity requirements. These authentication models cause pseudonyms management complex and revocation inconvenient. Blockchain seems to be suitable for storing the pseudonym certificates as transactions in the ledger, which enables distributed authentication. However, blockchain produces high latency for the membership verification of users. To tackle these problems, we present an Efficient Privacy-preserving Authentication Model (EPAM), leveraging the asynchronous accumulator to extend the blockchain application. The asynchronous accumulator supports efficient membership verification and avoids the time consuming of checking the Certificate Revocation List (CRL). Additionally, by designing a mutual authentication protocol, we achieve privacy properties such as anonymity and unlinkability under the consideration of the semi-trust RSUs. The simulations show that the membership verification time is about 0.157ms in EPAM test over 10 certificates, thus alleviating the mutual authentication latency in VANETs.