LWE-CPPA: a scheme for secure delivery of warning messages in VANETs

Conditional privacy preserving authentication (CPPA) schemes preserve privacy of nodes and authenticate warning messages in vehicular ad hoc networks (VANETs). However, the existing key exchange processes are computationally expensive, which compel CPPAs to rely on temper proof devices with pre-installed keys. Moreover, transmission of messages occurs as plaintext, which provides an opportunity to adversaries to intercept and temper communication. Furthermore, CPPAs provide no means for dealing with blackhole attacks. In this paper, we present a novel light-weight encryption-enabled CPPA (LWE-CPPA) scheme that introduces encryption in warning messages. The scheme starts with the exchange of unique symmetric keys among nodes by using our proposed variant of Diffie-Hellman algorithm. After successful key exchange, the scheme uses our proposed VANETs specific novel lightweight encryption algorithm to yield a strong cipher for protection of messages from adversaries. An authentication process follows message encryption that makes our scheme robust. Furthermore, LWE-CPPA provides protection against blackhole attacks by employing a predefined threshold for warning messages acknowledgment. Simulation results demonstrate that LWE-CPPA provides improved security with reduced computational and communication overheads as compared to eminent CPPA schemes.