Protocol Filtering Diodes for One-Way Data Flows

This technical report discusses the implementation of Protocol Filtering Diodes (PFDs) designed to enhance the security of one-way data flows from operational technology (OT) networks to IT environments. It outlines the challenges faced by defense and critical infrastructure teams in transferring sensitive data without exposing command-and-control systems to potential attacks. Traditional data diodes are noted for their hardware-enforced unidirectional flow but are limited by software controls that may compromise data integrity. The report details how PFDs, such as Owl Talon One and Owl Talon Torrent, provide an additional layer of security through FPGA-based protocol validation and reconstruction. This ensures that only mission-critical data is transmitted while blocking malformed or malicious traffic. The document also presents a use case for deploying PFDs to facilitate secure one-way analytic feeds, ensuring compliance with U.S. Government High Threat Network mandates and Zero Trust principles. Key features include deep inspection capabilities and scalability options.