Unidirectional Security Gateway and Data Diode Guide

A unidirectional security gateway is a hardware cybersecurity solution that ensures unidirectional information transfer between two networks. Traditionally relying upon a fiber optic connection to enforce one way data transfers, data diodes may encounter transmission reliability issues and data overruns, while modern unidirectional security gateways include assured delivery mechanisms to overcome these challenges. Unidirectional gateways and data diodes have been common for decades in high-security environments, such as defense and intelligence agency facilities.

With the rise of industrial IoT and digitization, unidirectional security gateways are increasingly being deployed by private enterprises to securely transmit data generated by industrial control and safety systems.

This includes nuclear power plants and other electrical power generating facilities, manufacturing facilities, and transport systems to other networks (including the public Internet) while the gateways protect the networks containing these systems from attack.

Unidirectional means data can travel in only one direction. A reasonable way to think of unidirectional security gateways is as “one-way valves for data”, allowing data to flow out, without a way back in. A common scenario is where unidirectional gateways provide one-way data transfers from a high-security network towards a network with a lower security level. Data can be transferred while the high-security network stays protected from attack using that connection. In this scenario, the diode is protecting the systems in the high-security network producing the data being transferred.