KNX Secure for Planners & System Integrators

New regulatory frameworks – such as NIS 2, the GDPR or the Cyber Resilience Act – are placing clear demands on planners and specifiers: IT security is no longer an optional extra in building automation, but a mandatory element of responsible project design.

KNX Secure provides the technical foundation to implement these requirements in line with relevant standards – while also ensuring that projects are secure, transparent and future-proof.

On this page, you will learn:

• How legal and regulatory obligations can be translated into concrete planning decisions
• What to consider when it comes to tender specifications, device architecture and key management
• How to avoid unnecessary risks through clear structures and secure documentation
• Only those who integrate security requirements from the outset can design KNX projects that truly stand the test of time.

Note: Security legislation and industry standards vary between regions. The frameworks mentioned here reflect the European context, but similar requirements are emerging internationally.

Building automation systems are becoming increasingly connected and more exposed to attack. That’s why security can no longer be treated as an afterthought. It must be part of the planning process from day one.

The traditional notion of a closed KNX system is outdated. IP interfaces, visualisation tools, mobile devices and remote access are now standard – but also introduce potential vulnerabilities. If security is only addressed during commissioning, it’s often too late.

Take this example: If presence detection in a classroom is transmitted without encryption, it could lead to a data privacy issue – or expose the system to exploitation.

At the same time, legal responsibilities are increasing for project stakeholders. Regulatory frameworks such as NIS 2, the GDPR and the Cyber Resilience Act (in the European context) are making IT security a binding part of building automation planning.

What does this mean for project planning?

• Security must be addressed early – not postponed until commissioning.
• Clients expect clear specifications for encryption and access control strategies.
• Project stakeholders are responsible for the secure handling of certificates and cryptographic keys.

Lack of planning in this area can cause delays, raise compliance concerns, or lead to issues during tendering and handover.

With KNX Secure, all security-relevant data is centrally managed in the ETS – forming the backbone of every Secure-enabled KNX project.

The ETS is not only the standard planning tool for KNX, but also the central security authority within the KNX Secure ecosystem. In ETS, you can:

• define the overall project structure
• import all FDSK certificates (Factory Default Setup Keys)
• generate Tool Keys and Group Keys
• manage all security-relevant parameters and configurations

Access to the complete ETS project file is essential; only those who possess it can commission, modify or recommission Secure devices. If this file is lost or poorly documented, the entire system may become unusable.

For highly sensitive installations, an additional security measure can be applied: the BCU Key – a manufacturer-specific device key that prevents unauthorised changes to a device’s configuration. Only those who know this key can reprogram the device. This protection is highly effective but only if the overall key management is also properly structured.

Key recommendations for secure project handling:

• Archive FDSK certificates centrally and digitally
• Back up project files regularly (encrypted and versioned)
• Define clear responsibilities and access control policies

ETS is the security anchor of KNX Secure – and careless handling of this system can jeopardise the long-term integrity of your entire installation.

In KNX Secure projects, it’s not enough to include just a few devices with Secure functionality. What matters is whether the entire communication group – that is, all devices associated with an encrypted group address – supports KNX Secure. If even one device is not Secure-capable, the entire connection remains unencrypted and thus vulnerable.

For applications with elevated security requirements – such as in public buildings or where remote access is used – only Secure-compatible devices should be installed. Equally important is that the project is built on a stable, clearly structured infrastructure, and that all available security features of the selected devices are fully utilised.

Depending on the system architecture, either KNX Data Secure (for TP or RF) or KNX IP Secure will be used. The software environment is also crucial: ETS version 5.7 or higher is required to support Secure functionality.

Devices that support KNX Secure are usually labelled by the manufacturer – often with an “S” or “X” in the product name.

Device selection should therefore be guided not only by functional requirements, but also by the overall security strategy. Those who define early on which telegrams need to be protected can plan the appropriate components in a targeted manner – laying the foundation for a consistently secure KNX system.

Most problems don’t stem from the technology itself but from a lack of planning, documentation and coordination.

KNX Secure introduces new levels of protection – but only if the project is also well-organised on a structural and procedural level. Many issues don’t occur during installation, but much earlier. Typical pitfalls include:

• Loss of the KNX Secure Code (FDSK) – for example, if the sticker is removed or discarded during installation. Without this individual key, the device cannot be securely integrated. The code is supplied only once and appears on a detachable label – it must be stored safely and included in the project documentation.
• Encryption of telegrams despite mixed device groups – a common mistake: if not all participants in a group support Secure, the transmission will not be encrypted, even if intended.
• No backup of the project file – risking complete system failure if the file is lost.
• Unknown or lost ETS password – preventing any future expansion or maintenance of the system.

Things become especially critical when multiple trades or contractors are involved but no clear handover or key management structure exists. This can lead not only to security vulnerabilities, but also to delays, cost overruns, and a loss of client confidence.

Even after commissioning, the system should be monitored regularly. Missing telegrams, unexpected device behaviour or recurring errors may point to configuration issues or security-related problems. KNX Secure devices offer enhanced diagnostic features such as failure logs or download counters – those who understand and use these tools can detect suspicious activity at an early stage.

Pro tip:
Before the project begins, create a structured KNX Secure checklist that covers FDSKs, device selection, ETS version, group addressing, key management and project documentation. Coordinate this checklist with clients and project partners – and ensure a traceable handover. This protects not just the system, but also your position as a trusted integrator.