A Survey on Sybil Attack in Vehicular Ad-hoc Network

Vehicular Ad-hoc network is new and emerging technology.Researchers are gaining interest in this technology.Due to its open nature it is vulnerable to various attacks.Sybil attack is one of them.Various defense techniques have been given by researchers.In this work we briefly explain those defense techniques, given recently.We categorize these techniques as trusted certificates base, resource testing based and social network based.We give an overview of some defense schemes based on first two categories.We also give a summary of the techniques given in this paper, which is based on some parameters used in those techniques.