RSU-independent Message Authentication Scheme using CRT-based Group Key in VANET

Jin Sook Bong, Yu Hwa Suh, Ui Jin Jang, Yongtae Shin

http://doi.org/10.5626/JOK.2019.46.3.277

Security in communication is still an important issue because information transmitted via VANET provides safety-related services to drivers. In this context, there have been many studies related to the sending and receiving messages securely in VANET. In many studies, the RSU was assumed as a trust or semi-trust device and RSU played an important role in message authentication. However, a large number of RSUs cannot be considered trustworthy because the security of the RSU cannot be secured. Therefore, this paper proposes a message authentication scheme that is not dependent on the RSU. For this, a group key based on CRT (Chinese Remainder Theorem) is used. In the proposed scheme, the CRT-based key server calculates and distributes a `private key` and a `group key seed` to each vehicle. Then, each vehicle extracts the group key from the group key seed and uses it to authenticate the message. The proposed scheme eliminates the RSU dependence in a message verification. And it is also possible to easily withdraw a vehicle from a group.