摘要:Device-to-Device (D2D) is a major part of 5G that will facilitate deployments with extended coverage where devices can act as users or relays. These relays normally act as decode and forward relays (semi-intelligent devices) with limited computational and storage capabilities. However, introducing such a technology, where users can act as relays, presents a wide range of security threats, in particular, rogue relay devices or man in the middle attacks (M-I-T-M). Second, passing fewer control messages is always advisable when considering authenticity and secrecy. To mitigate M-I-T-M and to reduce communication costs, this paper presents a lightweight elliptic-ElGamal-based authentication scheme using PKI (FHEEP) in D2D communication. Pollard’s rho and Baby Step, Giant Step (BSGS) methods are used to evaluate the authenticity and secrecy of our proposed scheme. The communication cost is calculated based on the comparative analysis indicating that our proposed scheme outperforms the baseline protocol. The proposed scheme can be used for any infrastructure architecture that will enhance the security of any D2D settings with better performance.