Vehicular ad hoc network (VANET) has been ahot topic in recent years. Currently, VANET research mainlyfocuses on enhancing road safety, traffic safety warning, andreducing traffic accidents. In the future, the security of vehiclecommunication ought to be considered to protect privacy ofusers, such as personal ID and vehicular route. In order toenhance public service vehicles management, ensure officialactivities, and reduce finance expenditure meanwhile, a secureofficial vehicle communication protocol for VANET isproposed in this paper. The proposal combines homomorphickey agreement, symmetric encryption, message authenticationand digital signature mechanism, etc. Based on the protocol, personal information of users can be better protected. Besides, the proposed scheme has properties of mutual authenticationanonymous, availability, non-repudiation and security, all ofwhich are beneficial to privacy protection.