Unmanned Aerial Vehicles (UAVs) depend on secure communication to function effectively and safely. In the literature, methods for securing drone communication have been proposed. However, symmetric cryptography is the foundation of the majority of these methods. The exchange of secret keys is the main weakness of these methods. For improved scalability, most of these proposed methods may be enhanced using authenticated key exchange. Elliptical Curve Cryptosystems (ECC) have demonstrated significant computational benefits for resource-constrained devices. A common approach for creating shared keys based on ECC is the Elliptical Curve Diffe-Hellman. However, it suffers from Man-in-the-Middle Attack. This work presents an improved authenticated key exchange mechanism that utilizes hash chains and ECC. The design principle of the proposed protocol is based on Elliptical Curve Diffe-Hellman (ECDH) and the security validation has been carried out using AVISPA.