The pseudonyms are used to improve the privacy preservation efficiency of VANET users. Instead of using vehicle-s real identity information, the pseudonym-based methods utilizes pseudo identities for communication. The pseudonyms are necessarily linked with the real identity of vehicles for proper account maintenance. An attacker may infer real vehicle information based on pseudonyms. The pseudonym management methods change the pseudo-identity dynamically to disconnect the pseudo link with the vehicle-s real identity.