Location Dependent Implicit Public Key Scheme for Vehicle Communication Systems

Abstract

In a vehicle communication system, each vehicle transmits a BSM message including information about its location, speed, direction, etc. together with a signature of the message in a broadcasting mode once at regular intervals. The receiving side can use the signature of the received BSM message to confirm that the contents of the message are not forged/falsified and are normal. When generating the signature of the BSM message, the sender's private key is used, and the receiver's public key is used to determine whether the received BSM message is normal or not. In this study, a method was studied to allow the private key and public key used for message signature and verification to be changed according to location. The user who generates the signature holds a location-independent secret key (KRs), and based on KRs, a secret key that changes depending on the location (KRld-s) is generated. This location dependent private key is used in the message signature. A location independent public key (KUs) is stored in the certificate. The receiving side generates a public key (KUld-s) that changes according to location based on KUs, and uses it to determine whether the received message is normal. Therefore, the receiving side has the advantage of not needing to separately verify the location information.