This potential has sparked significant interest across industries and in academic circles. IoT evolving into a versatile utility, offering advanced capabilities in sensing, acting, communicating, controlling, and extracting valuable insights from vast amounts of data. However, there’s a big challenge: IoT devices often have limited computing power, memory, and battery life, which creates a major hurdle for security. To tackle this, our research introduces a new, energy-efficient, and lightweight cryptographic approach. It’s based on the ElGamal algorithm, specifically adapted for these resource-constrained IoT devices. In this study uses the ElGamal algorithm for key generation, encryption, and decryption. We’ve also included a comparative performance analysis using MATLAB, pitting our approach against RSA and Paillier algorithms. By employing an 8-bit manipulation technique, our proposed method significantly reduces power and memory consumption, making it ideal for energy-limited IoT applications. The results clearly show that our solution performs better in terms of power usage, memory requirements, and processing time, demonstrating its effectiveness for securing IoT devices.