# Empirical Evaluation of TLS-Enhanced MQTT on IoT Devices for V2X Use Cases
## 6 Discussion and Future Work Directions
_Implications and Future Work Directions._ This work demonstrates that TLS-secured MQTT communication is viable on IoT-class hardware when carefully configured, even under high-throughput or time-sensitive V2X scenarios. The interplay between cipher selection, network interface, and message composition reveals trade-offs among security, performance, and energy efficiency. Building on these insights, interesting future work directions emerge:  
1. Quality of Service (QoS) analysis under load and mobility: Although the current study focused on MQTT QoS level 1, further research could explore the performance implications of QoS levels 0 and 2 under different traffic intensities and mobility patterns. Evaluating packet delivery guarantees, retransmission overhead, and latency under WiFi and 5G mobility scenarios could offer critical insights for QoS selection in highly dynamic V2X contexts. 2. Feasibility in Ultra-Constrained Platforms (ESP32, ARM Cortex-M, etc. ): It would be worthwhile to assess the feasibility of TLS 1.3-secured MQTT on highly constrained platforms, such as ESP32 or ARM Cortex-M microcontrollers, which are common in low-power embedded deployment. Benchmarking these devices in terms of handshake execution time, memory usage, and cipher suite performance could help define minimum operational thresholds for secure communication in the most resource-limited environments. 3. Wireless Network Dynamics and TLS Session Robustness: Wireless environments are prone to jitter, handoffs, and dynamic IP address changes, all of which may affect the stability of TLS sessions. Investigating how these dynamics influence session persistence, reconnection latency, and throughput degradation, particularly in realistic multi-hop WiFi or 5G networks, would provide valuable evidence for secure session design in mobile IoT applications. 4. MQTT and CoAP Comparison in V2X Contexts: Another promising direction would be a comparative analysis of MQTT over TLS and DTLS-secured CoAP in realistic V2X environments. Such a study could examine key performance metrics, such as end-to-end latency, bandwidth efficiency, fault tolerance, and energy consumption, to determine the suitability of each protocol for time- and safety-critical applications such as hazard notifications or vehicular telemetry. Additional focus could be placed on the protocol behavior under network congestion and retransmission conditions. * Post-Quantum Cryptography on Resource-Constrained Devices: Finally, as TLS 1.3 evolves to support quantum-resistant cryptographic primitives, it would be interesting to investigate the feasibility of the Kyber, Dilithium, and SPHINCS+ algorithms [44; 45], recently standardized by NIST, on ARMv8-based IoT platforms. These schemes introduce larger keys and higher computational demands, raising questions about their impact on handshake latency, energy consumption, and memory usage. Future studies could explore both Key Encapsulation Mechanisms (e.g., Kyber-KEM) and Digital Signature Algorithms (e.g., Dilithium and SPHINCS+) in real-world IoT hardware, extending earlier simulation-based assessments such as those by [PERSON] et al. [11]. In summary, these future directions aim to build a comprehensive empirical framework to optimize secure and efficient communication across diverse V2X and IoT scenarios, while ensuring adaptability to emerging cryptographic standards and resilience to the threats of both the classical and quantum eras.