Design and Implementation of a Secure Data Transmission Protocol for IoT Devices in Smart Grids

Abstract

With the widespread integration of Internet of Things (IoT) technologies into smart grid systems, a large number of intelligent terminal devices are required to transmit data through networks in real time. However, the open network environment exposes data communication to various security threats, including eavesdropping, tampering, and replay attacks. Considering the limited computational capability and storage resources of IoT devices in smart grids, this study proposes a secure data transmission protocol based on elliptic curve cryptography and a lightweight identity authentication mechanism. The proposed protocol employs elliptic curve cryptography to accomplish key exchange and integrates the AES symmetric encryption algorithm to construct a hybrid encryption scheme, thereby improving encryption efficiency. In addition, device authentication is achieved through an identity-based authentication mechanism combined with random numbers and hash functions. Message authentication codes and a retransmission mechanism are further introduced to ensure data integrity and transmission reliability. The protocol was implemented on a Python platform and experimentally evaluated on representative IoT hardware environments, including STM32F407 and ESP32 devices. Experimental results demonstrate that, compared with the conventional RSA+AES encryption scheme, the proposed protocol exhibits significant advantages in encryption efficiency, communication latency, and computational overhead, while effectively resisting eavesdropping, tampering, and replay attacks. The findings indicate that the proposed protocol ensures robust security while maintaining favorable computational efficiency and communication performance, thereby meeting the practical requirements for secure communication among IoT devices in smart grid environments.