The proposed authentication and key exchange protocol for unmanned aerial vehicles (UAVs)are based on a combination of elliptic curve cryptography, symmetric cryptography, and blockchain technology. The protocol, called Blockchain-based Lightweight Authentication and Key exchange Protocol, aims to provide secure and efficient communication between the UAV and the ground station while minimizing computational costs and reducing the risk of cyber attacks. The elliptic curve cryptography is used for key exchange, symmetric cryptography is used for message encryption and decryption, and blockchain technology is used to store and distribute the public keys. The proposed protocol is evaluated through simulations and equated with current protocols. The outcomes show that the protocol has lower computational overhead, better security, and is highly resistant to attacks due to the use of blockchain technology. This makes the proposed protocol a suitable solution for secure communication in UAV applications. The paper builds on previous work such as DroneSecand DroneSec – lite, which is also based on elliptic curve cryptography and symmetric cryptography, but with a focus on lightweight authentication and key exchange protocols for UAV systems with varying computational capabilities.