Improvement in information technology (IT) necessitates the efficient interaction between wireless and mobile communication instruments. Correspondingly, wireless networks have experienced such a development in the present decade. Vehicular Ad-hoc Network (VANET) is an example. In VANET, different forms of information including safety information can be communicated. However, anonymity is one important challenge for such networks. Several solutions have already been suggested for realizations of anonymity including anonymity on the basis of the certificate of the anonymous, group signature and using Pseudonym. Though anonymity is important, malicious anonymity is also problematic. For instance, a member of the network may endanger the safety of other drivers by sending inaccurate traffic information. Hence, it is necessary to equip the network with a system to evaluate the accuracy of the data in spite of the anonymity of the vehicles. In case of identifying a misbehaving performance in the network, anonymity should be canceled. This will help the police detect and fine the mischievous vehicles and stopping the disseminating the fake traffic information. This type of anonymity is called conditional anonymity. One application of the conditional anonymity is to detect the vehicles involved in accidents. Several solutions have been suggested to detect such cases. They are usually Keywords: Vehicular Ad-hoc Network (VANET), conditional anonymity, Public Key Registery, Data centric behaviour detection, sybil Attack, false location information Detectinon
