Dynamic encryption based secure key management for Vehicle-to-Vehicle communication in autonomous driving

The emergence of autonomous vehicles has led to the need to establish a secure and effective Vehicle-to-Vehicle (V2V) communication system to support safety and trustworthiness in both highway and urban driving environments. Nevertheless, the traditional methods of encryption are not suitable in these dynamically changing networks because of the fact that change of network topology occurs regularly, real-time processing is to be achieved and also limited access to computational resources is available. This paper presents DASKM (Dynamic Autonomous Secure Key Management), a novel solution for secure key management that is based on dynamic encryption protocol especially used to support V2V communication in autonomous vehicle networks. DASKM takes advantage of adaptive key management approach where a hierarchical and decentralized key distribution algorithm is applied on the never-ending motion and communication among vehicles. Such an adaptive model will allow changes to be done in the encryption keys in real-time with respect to the contextual information thus maintaining strong data integrity and confidentiality even under high mobility rates. The proposed dynamic encryption protocol is lightweight having lowered the computational overhead to make sure that it does not jeopardize the security and still fits into the limited processing capabilities of in-vehicle units. Although decentralized key distribution introduces additional coordination overhead, DASKM minimizes this through three design choices: (1) AES-128 in CTR mode is selected for its stream-oriented, hardware-accelerable operation avoiding block-padding overhead; (2) key rotation is event-driven rather than continuous, triggered only when vehicle speed or proximity crosses defined thresholds, eliminating unnecessary computation; and (3) the hierarchical structure uses pre-computed group keys for platoon members, reducing per-vehicle key negotiation to inter-group exchanges only. As a result, computational overhead is maintained at 10-25 ms per packet, within the processing budget of standard in-vehicle OBUs. The term lightweight therefore refers to optimized overhead relative to the security level achieved. Wide-ranging simulations confirm the effectiveness of DASKM against man-in-the-middle, replay and spoofing, and latency is reduced by a factor of 30 per cent and security response times improved by 25 per cent compared to the fixed encryption models. Among other things, DASKM was shown to scale under a high-density fleet network, achieving stable throughput, and low latency, which is scalable to the predicted increase of the number of autonomous fleet vehicles. The results demonstrate that adaptive key management protocols such as DASKM can offer a practically scalable solution to secure V2V communication, and a stepping-tone to safer and more certain network of autonomous vehicles.