A Lightweight Pseudorandom Function Construction from One-Way Functions for Resource-Constrained IoT Devices

Abstract

The growing number of Internet-of-Things devices deployed in industrial, healthcare, and smart infrastructure settings has created urgent demand for cryptographic solutions that work within tight computational limits. Current pseudorandom function implementations such as HMAC-SHA256 and AES-CMAC provide strong security but require memory and power resources beyond what ultraconstrained microcontrollers can deliver, particularly those with less than 32 KB RAM operating below 100 MHz. This paper introduces a lightweight PRF built solely from one-way functions, the most basic cryptographic assumption needed to construct secure pseudorandom primitives. Our design uses a reduced-round SHA-256-based OWF that processes keyed inputs through an iterative, low-overhead structure tailored to embedded platforms with limited resources. We show through careful security analysis that this construction preserves pseudorandomness guarantees while running in 0.88 milliseconds on ARM Cortex-M0 processors, a 7.3-fold speedup compared to standard HMAC-SHA256 implementations. Testing across STM32L0, ESP32, and AVR ATmega328P platforms shows memory usage under 2 KB Flash and 208 bytes RAM. The PRF passes all fifteen NIST Statistical Test Suite assessments with p-values above 0.01. These findings show that OWFbased PRF designs can serve as practical, cryptographically minimal security solutions for nextgeneration constrained IoT systems.