Very Low Cost Entropy Source Based on Chaotic Dynamics Retrofittable on Networked Devices to Prevent RNG Attacks

TL;DR

This paper presents a low-cost, retrofittable entropy source based on chaotic dynamics, designed to enhance the security of networked devices against RNG attacks by providing high-quality randomness.

Contribution

It introduces a novel, inexpensive entropy source that can be easily added to existing devices using standard microcontrollers and communication interfaces.

Findings

Capable of generating over 32 kbit/s of entropy.

Compatible with multiple serial interfaces like USB, I2C, SPI, USART.

Operates reliably using a loop around a microcontroller's ADC.

Abstract

Good quality entropy sources are indispensable in most modern cryptographic protocols. Unfortunately, many currently deployed networked devices do not include them and may be vulnerable to Random Number Generator (RNG) attacks. Since most of these systems allow firmware upgrades and have serial communication facilities, the potential for retrofitting them with secure hardware-based entropy sources exists. To this aim, very low-cost, robust, easy to deploy solutions are required. Here, a retrofittable, sub 10$ entropy source based on chaotic dynamics is illustrated, capable of a 32 kbit/s rate or more and offering multiple serial communication options including USB, I2C, SPI or USART. Operation is based on a loop built around the Analog to Digital Converter (ADC) hosted on a standard microcontroller.