  Internet of Vehicles(IoV) is increasingly used as a medium to propagate
critical information via establishing connections between entities such as
vehicles and infrastructures. During message transmission, privacy-preserving
authentication is considered as the first line of defence against attackers and
malicious information. To achieve a more secure and stable communication
environment, ever-increasing numbers of blockchain-based authentication schemes
are proposed. At first glance, existing approaches provide robust architectures
and achieve transparent authentication. However, in these schemes, verifiers
must connect to the blockchain network in advance and accomplish the
authentication with smart contracts, which prolongs the latency. To remedy this
limit, we propose a privacy-preserving blockchain-based authentication
protocol(PBAG), where Root Authority(RA) generates a unique evaluation proof
corresponding to the issued certificate for each authorized vehicle. Meanwhile,
RA broadcasts a public global commitment based on all valid certificates.
Instead of querying certificates stored in the blockchain, the vehicle will be
efficiently proved to be an authorized user by utilizing the global commitment
through bilinear pairing. Moreover, our scheme can prevent vehicles equipped
with invalid certificates from accomplishing the authentication, thus avoiding
the time-consuming for checking Certificate Revocation List (CRL). Finally, our
scheme provides privacy properties such as anonymity and unlinkability. It
allows anonymous authentication based on evaluation proofs and achieves
traceability of identity in the event of a dispute. The simulation demonstrates
that the average time of verification is 0.36ms under the batch-enabled
mechanism, outperforming existing schemes by at least 63.7%.
