Protecting Privacy in VANETs Using Mix Zones with Virtual Pseudonym Change

Vehicular ad hoc networks VANETs use pseudonyms to communicate among them and with roadside units, these pseudonyms are used to authenticate these vehicles and to hide real identities behind these pseudonyms, to better enhance privacy, these pseudonyms are changed frequently so that it will not be that easy to link these pseudonyms together and hence reveal real identities. However, changing pseudonyms will not be that useful if previous and current pseudonyms are easily linked together. Therefore different techniques have been proposed to hide the pseudonym changes and make it difficult to link pseudonyms together. Most of these techniques do not fully quarantine privacy when changing a pseudonym under some situations such as low traffic. In this paper, we provide a technique for changing pseudonyms that have the same privacy level under all traffic conditions. The technique relies on fixed mixing zones that are planted and distributed over the roads. By this technique, a vehicle guarantees a high level of security when changing its pseudonym at that mix zone which will make it very difficult for an adversary to link particular pseudonyms together and hence reveal real identity. Performance analysis showed that our model works efficiently with very few computational costs.