Abstract

This study introduces a lightweight cryptographic system leveraging atomic switch based Ag/Ag2 S nanoparticle devices to enhance data security in resource-constrained IoT edge environments. Conventional cryptographic algorithms often require significant computational power and resources, making them unsuitable for such settings. To address this limitation, we propose a hardware-based encryption scheme that exploits the charge accumulation behavior and nonlinear electrical characteristics of Ag/Ag2 S devices. Analog electrocardiogram (ECG) signals were directly encrypted through voltage input manipulation, while signal decryption was achieved using an Echo State Network model trained to reconstruct input signals from output voltage responses. The encrypted signals exhibited a randomness successfully passing 12 out of 15 statistical tests defined by the NIST SP 800-22 suite. Furthermore, original ECG signals were accurately recovered with a reconstruction rate of 91.0%. These resultss underscore the promise of nanomaterial-based physical encryption as a viable and energy-efficient solution for secure data handling in future IoT edge applications.