Perimeter strategies are the traditional method of maintaining security for IT infrastructures. They can be thought of as a large medieval castle with high walls and an entry point over a moat keeping out any attackers. This leads to two fundamental assumptions: any user authenticated within the corporate network is safe – and once authenticated then the user will behave responsibly.

Within a tightly managed corporate infrastructure these assumptions are generally acceptable. However, as more users work remotely, more bring-your-own devices (BYOD) are encouraged by employers, and hybrid cloud working becomes the norm, these presumptions start to come under more scrutiny.

Question Assumptions

Zero trust is a security strategy that addresses these concerns and provides three fundamental tenets: never trust and always verify, implement least privilege, and assume a security breach.

It’s important to note that zero trust isn’t a single software application or a management directive, but is instead a whole strategy that involves every person within an organization as well as the technology.

Never trust and always verify usually falls within the thought domain of most technologists working in a broadcast facility, so this is nothing new for them. However, the IT methodologies must change where every device and user connected to the system is assumed to be a potential hack or security breach.

The concept of trust is a human attribute that we’ve always applied to computer security. We have varying understandings of what it means to be secure, but the actual effectiveness of security is biased towards our human emotions. For example, somebody we know within the organization may not be wearing their security badge. It might be that they have been fired from the company without our knowledge and no longer have a pass but have managed to get into the building and are looking to do something malicious. Most of us would assume they should be there but have just forgotten their pass. Indeed, the co-worker should be challenged, but few people would do this.

Thinking Ahead

These thought processes tend to spread into the security eco-system, and it takes a special type of person to spot and highlight them, the sort of person who assumes everybody is a threat. But if we all walked around assuming everybody was a threat then society would soon degenerate. But with some forward thinking, we can make zero-trust computer security effective without affecting society.

When a user logs onto the network, they are usually verified by the central authorization system to validate them, and with the perimeter wall approach they would be relatively free to gain access to most servers and processes. But we can improve on this with zero-trust methodologies and go further. For example, the user must validate the network they’re logging into to ensure they are not going to be a victim of a man-in-the-middle attack. Then each time the user accesses a network, server, or process, the central administration system can validate them again.

This may sound like a lot of work, but it isn’t. With secure certificates and authentication tokens, users can traverse the network without having to log in at every junction. But importantly, the secure certificates and authentication tokens are being constantly checked by every network access point, server, and process, thus keeping the infrastructure secure.

The processes, servers, and individual networks that make up the broadcaster’s infrastructure must be installed with security mechanisms such as digital certificates, cryptographic keys, and authentication tokens including certification or authentication certificates, and this is where the zero-trust thinking starts to manifest itself. IT departments should not allow an application to be installed if it cannot be verified using one of these secure methods.

Least privilege is the idea of only providing users with read, write, and execute access as needed for their role. It’s very easy to give every SoftDev engineer access to every project in the software repository. But this has the potential to cause massive security issues, especially when considering disgruntled employees, or even a breach of a user’s login credentials. In this case, only the specific projects a SoftDev engineer is working on should be made available to them.

Keeping Logs

There should be a formal audit process governing user access to networks, servers, storage systems, and applications, together with regular reviews of assigned privileges.

It might look like there is a lot of process going on and it’s fair to say, compared to the old ways of broadcast attitudes to security, there are. But these processes not only protect the here and now; they also allow IT specialists the opportunity to forensically investigate breaches should they occur, and this is incredibly important for learning from mistakes.

Assuming a breach in security further improves system designs. For example, we should question what happens to all the high value media assets if the storage system is breached. Should they be ringfenced with alarms so that every time a user accesses this area a notification is sent? Or, if we assume that an encryption virus successfully attacks, what will be the impact on stored data and the overall business?

It might seem that we are running the risk of falling down a deep and winding rabbit hole with this type of thinking, but what we have done is engaged in risk management as well as prevention. By assuming that a hack or breach will occur, we can more effectively assess the risk and impact to the business.

Broadcast Applications

The principles of zero trust become particularly important as broadcast workflows become more distributed. For example, a cloud playout system consisting of automation, graphics, subtitle generation, compliance recording, media asset management, and monitoring all operate as independent and often isolated services. In a traditional perimeter-based model, these applications may be permitted to communicate freely once they are connected to the broadcaster’s internal network.

Using zero trust, every interaction between system services is verified and authenticated. The graphics service must prove its identity before receiving schedule information from the automation system, and monitoring services must authenticate before accessing operational metrics. Even though all services may be operating within the same datacenter or cloud environment, none are implicitly trusted.

The same principles apply to human operators. A transmission controller may have permission to start and stop channels but should not automatically gain access to content archives, financial systems, or software repositories.  By restricting privileges to only those required for a specific role, the impact of compromised credentials can be significantly reduced.

As broadcasters continue adopting remote production, cloud playout, and software-based infrastructures, the number of devices, users, and services participating in workflows will continue to increase. Zero trust provides a framework that allows these complex systems to scale securely without relying on the outdated assumption that anything inside the network perimeter can be trusted.

Zero-trust methodologies are more than just a new process or software application; they represent a fundamental shift in the way broadcasters design, operate, and secure their infrastructures. Throughout this series we have explored technologies such as authentication systems, RADIUS, NATS messaging, EBU R143 recommendations, and other security mechanisms. Zero trust brings these concepts together into a unified strategy where every device and user connected to the system is assumed to be untrusted until verified.

As broadcast infrastructures become increasingly complex, the ability to monitor, audit, and forensically investigate security events becomes just as important as preventing them. Zero trust therefore provides not only a stronger security footprint but also a framework for managing risk in an industry where content, reputation, and operational continuity are critical assets. As broadcasters continue their transition from dedicated hardware facilities to highly distributed software platforms, the principles of zero trust will become a fundamental part of everyday engineering practice.