The dynamic nature of Vehicular
Ad-hoc Networks (VANETs) necessitate suitable authentication schemes to
prevent intruders from compromising the privacy of vehicles. In order to maintain the privacy of vehicles, several schemes using pseudonyms instead of real IDs of vehicles have been proposed in the literature. When vehicles use
pseudonyms instead of their real IDs in their communication,
authenticating the vehicles becomes an issue. Assigning a single
pseudonym to a vehicle does not solve the problem because, based on a
vehicle's trajectory, an intruder can track the
vehicle. So, a vehicle needs to change its pseudonym frequently. So,
to ensure the privacy of the vehicle, each vehicle should be assigned a pool
of pseudonyms, and the vehicle should be able to pick a pseudonym from the pool and
use it and also change its pseudonym periodically. In many of the existing works, for authentication
purposes, a central entity is used to issue certificates corresponding to each
pseudonym assigned to a vehicle and distribute them to the vehicle so it
can present the certificate to authenticate itself. However, this
approach involves significant computation, storage, and distribution
overhead of the revoked certificates of pseudonyms of malicious
vehicles because each vehicle is assigned a large number of pseudonyms.
We address this issue and propose a Low-overhead and Efficient
Privacy-preserving Authentication (LEPA) scheme for VANETs by
leveraging Merkle Hash Tree (MHT) and Cuckoo Filter (CF). We analyze
and verify the robustness of the LEPA scheme against various
attacks. The performance evaluation demonstrates the efficiency of the
LEPA scheme with respect to authentication overhead.