This paper presents a lightweight keyed hash function for resource-constrained Internet of Things (IoT) environments. The function utilizes the chaotic properties of the Parabola Chaotic Map to generate a secure hash value. The proposed hash function achieves efficiency by employing a simple structure, minimal iteration loops, and initial conditions as security keys while maintaining strong security properties. Extensive experiments, including hash sensitivity analysis and statistical analysis, demonstrate the effectiveness of the proposed approach. The results highlight the function’s high sensitivity to input changes and robust statistical characteristics, aligning with established standards for cryptographic hash functions. This research contributes a promising solution for enhancing security and privacy in IoT systems, offering a lightweight and efficient keyed hash function based on chaos theory.