Establishment and focus: This study proposes a method that a vehicle can automatically change its MAC address for anonymity in vehicle communication system. After a shared key is established between the two cars participating in the communication, the two cars can use this shared key to generate and use a large number of new MAC addresses. Vehicles not participating in the communication cannot know the newly changed medium access control (MAC) address, thereby ensuring anonymity of the vehicle communication.

System: The sender and the receiver can calculate hv(i) = HMACSHA512(rs, CertA, CertB) using the shared secret number rs, and can generate up to 10 MAC addresses in one hv(i). The HMAC used for the calculation of each hv(i) uses rs which is secretly shared by the sender and receiver, so that the attacker cannot find out the generated MAC address. In this study, it is assumed that the vehicle communication system is made according to the IEEE WAVE standard. Therefore, the key value is shared between the transmitter and the receiver by using ECIES (Elliptic Curve Integrated Encryption Scheme). However, even if this study is used in a different environment, the results of the study can be applied as long as the transmitting and receiving vehicles share the same key value. The vehicle transmitting the MAC frame can guarantee anonymity of the vehicle communication by arbitrarily changing its MAC address.