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Learn About Data Diodes

What is a data diode?

A data diode, also called a unidirectional gateway, is a type of cybersecurity hardware that protects networks and other infrastructure by only allowing the data to flow in one direction. 


Data diodes are preferred for high-security environments like defense, industrial control systems and more. Once reserved for extremely critical applications, like the protection of nuclear power plants, this technology’s cost and complexity have decreased significantly in recent years. Diodes now present a practical choice for industrial and utility cybersecurity.

How do data diodes work?

Data diodes are hardware cybersecurity devices that utilize two optically-separated circuits to send data in only one direction using light. One circuit can only send data via light and the other can only receive it. All inbound traffic is stopped by the diode because the hardware does not provide light to shine in the reverse. This makes data diodes into one-way valves for data, providing physical security.

Data diodes provide connectivity to the Industrial Internet of Things and the security of an “air gap.” Operators can transmit equipment status without any possible way for hackers to control industrial equipment, inject ransomware, or use legacy systems as a backdoor to business information systems.

Who uses data diodes?

Data diodes are ideal for all types of commercial and industrial IT and OT environments that need data visibility while maintaining high security and are becoming increasingly rugged and affordable, expanding their uses. They can be used to protect data from sensitive equipment and critical infrastructure control systems. Our current applications of data diode protection include: 

  • Energy and Utilities

  • Oil and Gas

  • Manufacturing

  • Waste and Water Treatment

  • Transportation and Logistics

  • Healthcare Facilities


Learn more about our data diode solutions in different industries

Common Questions About Diodes

What are the benefits of using data diodes?

Today’s internet was designed around two-way communication. This setup inherently introduces cybersecurity vulnerabilities even when a truly one-way function, like equipment monitoring, is desired. Data diodes enable secure access to online monitoring and predictive analytics, allowing:

  • Increased Efficiency

  • Decreased Unexpected Downtime

  • Increased Staff Productivity

Can a data diode be hacked?

Hackers cannot penetrate a data diode remotely. Data diodes are designed to be highly secure by using physics (light) instead of software to provide protection. They are also typically built with multiple layers of security, including encryption and access control mechanisms.

What are the limitations of using a data diode?

Since data diodes only allow data to flow in one direction, applications are limited to unidirectional use cases like cross-domain data transfers, equipment monitoring, and data exfiltration. If your use case requires remote access or control of assets, a bidirectional data flow may be better suited for you.

What is the difference between a firewall and a data diode?

Data diodes are a type of hardware designed to be uncompromisable. Their physical design ensures data security, and they are one of the strongest cybersecurity tools to select.

Firewalls are created using flexible code and are designed to filter out and stop threats using logic to identify “bad” traffic. Firewalls are not unidirectional and allow information to pass through both ways, opening up potential threat entry points. Threats are always evolving new ways of defeating firewall logic.

Learn more here about the differences between firewalls and data diodes.

Fend’s Data Diodes

Fend makes robust, affordable data diodes to protect industry, utilities, critical infrastructure, and our modern way of life. Browse our data diode products and contact us with any questions!

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