Distance-dependent Encryption Mechanism For Vehicular Ad Hoc Networks

Vehicular ad hoc networks(VANETs)is a kind of self-organizing wireless multihop networks that consists of On-Board Unit(OBU),Road-Side Unit(RSU),service providers,and trusted certificate authority(CA).It can provide road traffic information beyond the visual distance for people inside the vehicle.In VANETs,a vehicle periodically broadcasts messages to a circular area centered on itself and within its horizon.The content of the messages includes the sender’s speed,direction,braking state,and additional information related to the vehicle itself.These messages are required by driving aids,such as collision warnings and lane change alerts,but they are a potential source of danger.Because the messages sent by vehicles are frequently closely related to the privacy of the people in the vehicle,they incur the risk of a privacy breach during the communication process.Attackers can use these messages for information collection,forgery,vehicle tracking,and other destructive activities.As a result,not only is personal privacy threatened,but also these messages may lead to traffic chaos and even accidents.Therefore,addressing the topic of VANETs communication security,in this paper we propose a distance-based security encryption mechanism for VANETs: distancedependent encryption(DDE).If a vehicle periodically broadcasts messages to a circular region centered on itself,other vehicles also located in this circular area have different degrees of difficulty in decrypting the message because of the difference in their distance from the sender.The further the distance between the recipient and the sender,the greater the time cost of decrypting the message,presuming that the message can be received.In this way,the receiver at a longer distance will spend a greater price to obtain the message of the sender than the receiver at a closer distance,so the longer it takes to decrypt the message,the harder it is to decrypt.Aiming at the above mechanism,a specific encryption method is presented.By improving the Rivest-Shamir-Adleman(RSA)and Data Encryption Standard(DES)algorithms and then combining them,a mechanism that accords with the above hypothesis is realized.Finally,we verify the accuracy of our analysis and prediction and the reliability of the mechanism through detailed simulation results and use a function on the safety strength to prove the security of the mechanism.