The proliferation of distributed, decentralized governance structures in large operational technology (OT) environments poses cybersecurity challenges to large industrial companies. Business environments today are increasingly digital, and cyber-attacks are more prevalent than ever. This has led to the development of various network security technologies to ensure the protection of organizational data and infrastructure. Data diodes are becoming increasingly useful for providing one-way data flow as part of these governance structures. Hardware devices such as these typically provide a physical and electrical separation between the source and destination networks, allowing for one-way closed data transfer.

As a result, industrial network monitoring can be performed without exposing internal networks to the increasing risks associated with external threats. The data diode was developed decades ago and is used by thousands of organizations around the world today, but many people, including cybersecurity professionals, have never heard of it, or have only heard inaccurate descriptions. Here is a description of data diode technology, how it works, and how it helps secure critical networks, systems, and data.

What Is Data Diode?

A Data Diode “unidirectional security gateway” is a hardware device which is assimilated to a network security layer which allows information to flow between different networks with different levels of security.

Sensitive networks contain valuable and classified information. One method of doing this is to isolate the networks, making them inaccessible to all outside networks. It is sometimes necessary to transfer sensitive information between these networks, regardless of their nature.

A data diode is a cybersecurity solution that ensures one-way information exchange, This high-assurance hardware device maintains both network integrity by preventing intrusion, as well as network confidentiality by protecting the most security sensitive information.

It is imperative that data links connected to the internet of things or Industry 4.0 networks are reliable, secure, and safe. Nowadays, even networks that are secured with traditional security methods are vulnerable to cyberattacks. A data diode, which is both a hard- and software device, solves this problem by allowing only data uploads to the external world and preventing backward data downloads for security reasons.

Cyber security with data diode extends the capabilities of traditional solutions for network security. Researchers have found that cyberattacks are proof of the importance of safe and secure networks.

The study found that the number of Trojans, ransomware, and trickbots increased in billions and that the intensity and variation of the malware continued to increase. The security requirements for the interconnected industry and in critical infrastructures are extremely high, and industrial equipment interfaces must be fully protected. It is also important that the data transmitted do not allow for manipulation and confidentiality

How Data Diode Works?

The data diode is a device that allows data to be transmitted from one segmented network to another in a safe and secure manner. By using data diodes, source and destination networks remain physically and electrically separate, thereby enabling non-routable, one-way data transfers.

It is a device that prevents data from being sent in the opposite direction and acts as a non-return valve between
two networks. The data transfer is based on the hardware and optical fiber so it is physically not possible for data to
be transferred in opposite direction. As this cyber security with data diodes is not based on software, so there are no
proneness in the form of software bugs or malicious code. This Hardware based security with Data diodes provide
High Secured networks assurance.

Data diodes are hardware-based electronic devices with two circuits, one sending and one receiving, that restrict data transfer to one direction only and create an “air gap” between the source and destination networks. With the use of data diodes, we can make highly secured SCADA systems and it is also a secure way of IT-OT integration network data transfer using Bilateral/Bidirectional transfers. Data diode is a cybersecurity solution that ensures that information travels only one way. Data can only be transferred forward using an optical fiber with a sender on one end and a receiver on the other. This means there is no two-way transfer, preventing leakage and manipulation from taking place.

If a data diode is directed from the high-security network towards a network with a lower security level, data can be transferred while the network stays protected. By sharing information via a data diode, you are guaranteed that no one can use the same connection in the opposite direction to reach the secure network and manipulate its environment.

Applications Of Cyber Security With Data Diodes

Applicability of data diode technology goes beyond the realm of critical national infrastructure. Many Industrial Automation systems run on old software and machinery, which make them vulnerable to cyberattacks. The use of data diodes in this type of legacy system allows more security to be achieved without removing or updating the system and possibly exposing it to more threats.. Due to its effectiveness Data diodes are used in many areas for variety of application areas

1. Highly Secured SCADA (Supervisory Control and Data Acquisition) Systems

2. Bilateral/Bidirectional Transfers using Multiple Data Diodes for Control and Monitoring

3. Backup and disaster recovery archive

4. Data transfer from IOT sensors network.

5. Sending and Receiving alarms and Events from a confidential network

6. Sending and Receiving emails from an open network to a confidential network

Difference Between Data Diode And Firewall

The primary difference between data diodes and firewalls is that data diodes provide an electrical and physical separation layer, designed to pass one-way traffic between segments to eliminate attack risk. Firewalls contain configurable code and policies that can be used to stop or redirect flagged traffic.

Network security relies heavily on firewalls, which are good information security tool. Firewalls stop, filter, or redirect traffic between external and internal networks in response to decisions from a policy engine built into the system. Since firewalls rely on policies and are software-based, attackers can sometimes exploit configuration errors to circumvent them. There is also the option of exploiting existing vulnerabilities in the firewall itself, allowing them to control it and admit anything they want.

The data diode is also a security barrier, but it uses one-way data transfer protocols to enforce a physical separation between network segments, eliminating backdoor attacks. Data diodes, unlike firewalls, are physically forced unidirectional traffic using hardware-based security mechanisms – allowing data to flow in one direction and preventing potential attackers from accessing data


The usage of data diodes has been primarily confined to networks that require high-level security, applicability of this technology goes beyond the realm of critical national infrastructure and IACS/SCADA. All the sectors such as aviation, automotive industry, financial services, health care services, accounting, legal services, or small manufacturing plants would also benefit from the implementation of data diodes. It is equally important to promote the adoption of data diode technology in legacy systems. Parijat Controlware. Inc proposed data diode hardwareenforced solution will enhance a wider arsenal of cybersecurity tools. Furthermore, this technology should have the ability to monitor and respond quickly to materialized threats due to its hardware-based characteristics.