Broadcast and Silence Period (BSP): A Pseudonym Change Strategy

Abstract

Vehicles in Internet of Vehicles must constantly broadcast basic safety messages to keep other vehicles informed of their location, speed, and other parameters. Attackers can use the content of these messages to follow the path of the vehicle and invade vehicle owner privacy. Vehicle location privacy was ensured by broadcasting these messages using pseudonyms and periodically changing these pseudonyms. However, in mix-zone-based strategies, vehicles are frequently restricted from changing their pseudonyms in specific places. Furthermore, most previous change strategies only safeguarded against the syntactic linking attack and did not account for the semantic linking attack. Thus, in this study, we proposed a broadcast and silence period pseudonym change strategy to overcome these difficulties. Mix zones were obtained by analyzing the locations where vehicles frequently stop. The vehicle broadcasts or silences in a mix zone according to our broadcast and silence period strategy and changes to the pseudonym assigned by the road side unit during the silence phase until it leaves the zone. Our safety analysis and experimental results indicate that the broadcast and silence period prevent both linking attacks while reducing the impact of radio silence on vehicle safety by limiting the silent time, thereby providing better location privacy protection for vehicles compared with the existing schemes. In addition, the number of signatures required to be verified each time it receives messages and the overhead incurred in changing pseudonyms for vehicles is acceptable.