Preserving privacy is imperative in the new unmanned aerial vehicle (UAV)-assisted mobile edge computing (MEC) architecture to ensure that sensitive information is protected and kept secure throughout the communication. Simultaneously, efficiency must be considered while developing such a privacy-preserving scheme because the devices involved in these architectures are resource constrained. This study proposes a lightweight and efficient authentication scheme for the UAV-assisted MEC environment. The proposed scheme is a hardware-based password-less authentication mechanism that is based on the fact that temporal and memory-related efficiency can be significantly improved while maintaining the data security by adopting a hardwarebased solution with a simple implementation. The proposed scheme works in four stages: system initialization, EU registration, EU authentication, and session establishment. It is implemented as a single hardware chip comprising registers and XOR gates, and it can run the entire process in one clock cycle. Consequently, the proposed scheme has significantly higher efficiency in terms of runtime and memory consumption compared to other prevalent methods in the area. Simulations are conducted to evaluate the proposed authentication algorithm. The results show that the scheme has an average execution time of 0.986 ms and consumes average memory of 34 KB. The hardware execution time is approximately 0.39 ns, which is a significantly less than the prevalent schemes, whose execution times range in milliseconds. Furthermore, the security of the proposed scheme is examined, and it is resistant to brute-force attacks. Around 1.158 × 10 77 trials are required to overcome the system's security, which is not feasible using fastest available processors.