Abstract
Vehicular Ad Hoc Networks (VANET) is a technology that has been recently emerged, and bring a lot of interests. VANET can be used to improve road safety, reduce road traffic, serve interests of its users, and provide emergency services. The security is one of the most important issues in VANET, it is considered a critical point in the development of robust VANET systems. In this paper, a diverse types of security challenges and requirements of VANET will be discussed, and a set of possible solutions for VANET security problems and attacks will be presented and analyzed. Also this paper will propose a new protocol that is called the reply protocol, this protocol aims to protect VANET against several attacks.