MANET Privacy - A sub group of mobile ad hoc network(MANET) that is vehicular Ad Hoc Network (VANET) that assists in, vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) intercommunications. An important characteristics of VANET consists of, highly dynamic, distributed networking and self-organizing topologies. In safeguarding billions of human live features of VANET and its uses regarding safety on roads drew attention towards huge amount of interest in academic fields and industries, moreover with study and development on enhancing the facilities of transport transit infrastructure. Major challenging and crucial security problems takes place during information transmission with open-access surrounding such as VANET. Non-repudiation, data confidentiality, Authentication, data availability and data integrity behave as a critical part of VANET’s security. Privacy preservation over VANET is major concern, in this research we will elaborate different attacks over VANET and will conclude how block chain based VANET will perform better and less error prone.