Vehicular ad hoc networks (VANETs) are gaining more and more interest in intelligence transportation system research fields. They allow optimized traffic management due to improved vehicle resource usage and real-time information exchanges. However, being in an open environment introduces different security and privacy challenges. Attackers can sniff radio signals and forge the transmitted information leading to sensitive data leaking or compromising. This paper examines the preservation of privacy information in VANET communications. We use the Active Bundle (AB) for vehicle authentication and data preservation based on software-defined networks (SDNs). Our proposal benefits from the SDN infrastructure to guarantee fluent centralized management while using the AB guarantees data integrity and confidentiality throughout its entire lifecycle. Analytical studies and simulations show that our solution efficiently preserves VANET users' privacy with minimal effects on network transmission quality.