||In recent year, Vehicular Ad Hoc Networks has many research to explore, VANET is a mobile communication technology, and the major utilize of the moving vehicles or transport facilities as a node, using wireless communication technology, and combined with the wireless device on the vehicle to constitute a mobile network. The purpose of VANET is utilizing these information which collected by road situation in the wireless broadcasting way, and sent this information to user on the road to improve the driving efficiency of road users and increase traffic safety on the road. When the vehicles sending message maybe suffer from the lots of malicious attacks, in order to prevent malicious attackers stealing, tampering, or spreading wrong information to the vehicle of legality. Therefore, when the vehicle broadcasts message to other vehicles, must through roadside unit help to do message authentication. Since the vehicles offer method of traffic information is important, sending message between vehicle and vehicle must be real time and computation of message authentication cannot too complex. In order to protect vehicle’s privacy and prevent the identity of vehicle exposure, we can utilize the anonymous identity to protect the secret of vehicle safety.|
In this thesis, we proposed the Chameleon Hashing Based Message Authentication, Private Communication and Revocation in Vehicular Ad Hoc Networks. In our proposed scheme, TA and RSU keep secret values to generate chameleon hash value, give neighbor RSUs and vehicles a new secret value to represent itself, when vehicle registers with TA to obtain public identity and proposes anonymous request to RSU then obtain anonymous identity, vehicles utilize anonymous identity to authenticate chameleon hash value and can verify other vehicle’s identity of legality, afterwards vehicles utilize technology of HMAC to verify message which was sent by vehicle of legality, utilize property of exclusive or to transmit message to specific vehicles and combine with its own secret value and technology of Diffie-Hellman key exchange to generate session key, and use session key to communicate with specific vehicles privately. When malicious attackers occur, TA and RSU can look up table, which record public identity and anonymous identity, to revoke malicious attacker’s identity in the revocation list. Afterwards, combined above function and satisfy security requirement of VANET, like authentication, non-repudiation, confidentiality, conditional anonymity and un-traceability.