Jun 15, 2023
4 min read

From Data Diodes to Dynamic Access: How Cyolo is Revolutionizing OT Security

Written By

Samuel Hill

There are many good reasons to keep a process control network isolated. Chief among these is the desire to keep it safe, operating, and productive. One way to enforce isolation is via strong segmentation of the operational technology (OT) network, keeping it separate from other networks and restricting communication between them.  

This "air-gap" between two networks typically has a "high" side and a "low" side. The high side network holds sensitive or critical information that needs to be protected, whereas the low side network is less secure and typically used for data acquisition or monitoring purposes. 

What are Data Diodes? 

For many decades, data diodes have played a crucial role in securing and controlling the flow of information between different networks or systems. A data diode is a unidirectional network device that allows data to move in only one direction while preventing any backflow or unauthorized communication.

Data diodes use optical or electrical signals in order to enforce one-way communication. They are designed to allow data to flow from the high side to the low side but to prevent any data from returning in the opposite direction. They often include added security measures such as protocol validation and content filtering.  

New Requirements for OT Connectivity 

Air-gapping was once a standard practice that largely protected OT networks from cyberthreats and other risks. However, today’s business reality often demands connectivity into the OT environment. How to fulfill the growing need for connectivity while keeping OT networks safe and secure remains an open question for many organizations. In this new world, sometimes called Industry 4.0, there are some gaps that data diodes cannot solve for. 

  • Remote Accessibility: Data diodes set up a unidirectional flow of data, which means that remote access to systems behind the diode is not possible without other mechanisms. 

  • Management and Maintenance: Administrators and technicians cannot remotely manage, monitor, and support critical systems found in OT environments.  

  • Real-Time Monitoring and Alerts: Data diodes do not send out alerts or notifications in case of anomalies, potential security breaches, or system failures. Such notifications enable prompt responses and help mitigate risks more quickly. 

  • Granular Access Control: Data diodes do not enforce access policies based on user roles, privileges or authentication factors.  

  • Secure Data Transmission: Extracting data from the OT system is a key benefit of Industry 4.0, but data diodes cannot ensure that data transmitted over the network is protected from interception or tampering. 

  • Audit and Compliance: Data diodes do not include logging and auditing functionalities, which would capture detailed information about remote access sessions.  

How Cyolo is Revolutionizing OT Security 

The Cyolo zero-trust access solution supplies robust security for OT environments and offers several significant advantages over traditional data diode deployments.  

First, Cyolo gives industrial enterprises unprecedented control over access with granular controls that adapt to the environment’s unique needs. No longer bound by one-way communication, organizations gain dynamic access control based on user identity, device posture, location, and context. Meanwhile, OT systems remain impenetrable to unauthorized access attempts. 

In addition, Cyolo takes security to the next level with TLS 1.3 encryption, which safeguards all sensitive data during transmission. Operating at the application layer, Cyolo empowers organizations to define access policies for specific applications or resources by granting granular control over who can access critical systems and data. Cyolo also liberates the workforce, including original equipment manufacturers (OEMs), vendors and external contractors, from the confines of physical access limitations.  

Secure Remote Access Becomes a Reality 

While data diodes and other security solutions have been unable to provide secure remote access, the Cyolo solution allows users (including third-party vendors and contractors) to connect from any (managed or unmanaged) device or location without compromising security.

And with seamless scalability and centralized management, administering access controls, user authentication, and authorization becomes effortless. Cyolo’s real-time monitoring and auditing capabilities let organizations stay one step ahead of potential attackers and also provide crucial visibility into remote access sessions and user activities. Any suspected security incidents or policy violations can be swiftly detected and responded to accordingly.

Purpose-built to safely connect people to OT systems, the Cyolo zero-trust access solution transforms security, productivity, and operational efficiency in the OT environment. It's finally possible to unleash the full potential of your systems while keeping them impenetrable. To learn more, schedule a commitment-free conversation with the Cyolo team.

Samuel Hill


Samuel is the Director of Product Marketing at Cyolo. Before cybersecurity, he spent 7 years working in the ER and loves to tell stories. He is the husband to one, father to four, lives in Bozeman, MT, and would rather be outside. He holds an M.A. in Strategic Leadership from Life Pacific University.

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