A secure and with a low cost updated information system in VANET

With the rapid development of information technology, telematics is gradually mature. The related vehicle equipment has become a developing goal of telematics industry. Now, users must disassemble navigation device and connect to a computer to update existed data. This way will cause inconvenient, and might miss many instant information. On the other hand, many companies are developing information system. When the user updates the information of vehicle-related equipment, the user can get a discount from subsidiary. Therefore, we proposed a secure scheme to reduce the computation cost and communication cost of vehicle-mounted device by using cryptography. In our scheme, navigation device can send and receive messages instant via the roadside unit. It is positive development for mobile commerce. Both of companies and consumers are beneficial.