Semantic-Driven Direct Authentication for IoMT Using an Enhanced Lotus Effect Optimization Framework

This paper proposes a novel hybrid authentication framework that combines offline and online verification to enhance security and performance in IoMT networks. In the offline phase, user and device identities are verified directly within the local area network (LAN), reducing latency and dependence on continuous server communication. The online phase employs a centralized authentication server to complete system-wide verification. The proposed method integrates Elliptic Curve Cryptography (ECC) for lightweight and secure key exchange, XOR operations for efficient credential combination, and one-way hash functions for ensuring data integrity. To further strengthen the authentication process, the Improved Lotus Effect Optimization Algorithm (ILEOA) is introduced to select the optimal cryptographic key, minimizing latency and improving resistance to attacks. The architecture is specifically designed to meet the constraints of IoMT devices while achieving multiple security objectives, including protection against replay, impersonation, and man-in-the-middle attacks.