A Privacy Conserves Pseudonym Acquisition Scheme In Vehicular Communication Systems

Vehicular communication systems rely on temporary anonymous identities,i.e.pseudonyms,to establish security and at the same time avoid the possibility of tracking vehicles.If a vehicle uses only one pseudonym,an adversary would be able to follow the vehicle by observing and linking messages,signed under that pseudonym.Therefore,the vehicles acquire a set of pseudonyms from the pseudonym certificate authority(PCA),i.e.infrastructure of the communication system,and switches pseudonyms frequently.If a vehicle would be unable to acquire these pseudonyms,it would not be able to utilize the communication system without compromising its privacy.Hence,security and privacy techniques proposed for conventional Vehicle Ad Hoc Networks(VANETs)pseudonym changing strategy may not scale well in such early deployment scenarios.We address this problem by giving a secure pseudonym scheme.A vehicle can create its pseudonyms using Gao Algorithm.However,a pseudonym issued by the PCA and a pseudonym created with a Gao Algorithm would look different to an observer.PCA issued one pseudonym for one vehicle after encryption sending to vehicles so Gao Algorithm automatically creating sub-pseudonyms that are using for 15 days,10 days that’s why very less complexity of pseudonyms management and less Memory required on PCA.If only one vehicle can use pseudonyms created with PCA,it would easily be singled out and tracked.This thesis proposes a solution to this problem,but also the broader problem of linking messages by other means,e.g.the content of the message.In the solution,a vehicle can generate its pseudonyms,using the Gao Algorithm scheme,and make them unlinkable at the cost of computational overhead for itself and the vehicles around it.The vehicle achieves this by aligning the lifetime of the pseudonym with other pseudonyms and asking neighboring vehicles to alternate randomly between using pseudonyms issued by the PCA and pseudonyms created with group Algo2.We develop a distributed optimization algorithm for the shuffling process and a novel mechanism for cars to change their pseudonyms.This alternation by neighboring vehicles decreases the linkability of pseudonyms created with Algorithm 2 without increasing the linkability of pseudonyms created by the PCA.This results in a tradeoff between reasonable computational overhead and acceptable linkability for pseudonyms and more security and privacy.