Detecting Sybil Attack with a Scalable Protocol

Abstract

Vehicular ad hoc networks (VANETs) are being increasingly advocated for traffic control. Security and privacy are two major concerns in VANETs. Unfortunately, in VANETs, most of the privacy-preserving methods are vulnerable to Sybil attacks, whereby a malicious user can act as if to be multiple (other) vehicles. To ensure the authenticity of the messages propagated in VANET, a straight-forward process is to use public keys authorized by a certification authority (CA) to sign the messages. The certified public keys are called “pseudonyms”. On the other hand, in order to prevent vehicles from being tracked by categorizing the keys that are utilized, each vehicle can switch between multiple pseudonyms, which are difficult to correlate to each other.