Abstract—In this article, we present a security model architecture for communications, it offers a lightweight authentication in real-time, decentralized, efficient, that can be applicated in real mode, the proposed model respects the security requirements authenticity, anonymity, integrity, and non-repudiation. In our scheme, we firstly initialize the authentication between vehicle and RSU, the vehicle has an Access Token and key to join the group, then we use a hash message authentication code (HMAC) to avoid time consuming CRL checking. Finally, the vehicle can be using the generated Access Token for communication. The performances show that our model is more efficient in terms of authentication speed and consuming resources, it results a real time authentication.