Secure IT instead of IT security


Trusted Entity Operating System

HENSOLDT Cyber is revolutionising cyber security from the ground up, at the core. Based on the resilient seL4® microkernel, HENSOLDT Cyber is leveraging its extraordinary security features to develop a new operating system for embedded IT

HENSOLDT Cyber is changing 

the rules of the cyber security game

Based on seL4®

The seL4 microkernel belongs to the family of L4 microkernels and is the world's most advanced OS kernel due to its high assurance. It introduced two main security design concepts: the utilisation of capabilities and the application of formal verification techniques. Capabilities hereby represent a form of access token that allows for a very fine-grained control over system resources and therefore supports the kernel’s isolation properties. In addition, due to being formally verified, the absence of bugs inside the kernel implementation is proven with respect to its specification. 



TRENTOS is a seL4® based operating system. With the Trusted Entity Operating System (TRENTOS), HENSOLDT Cyber provides secure IT from the bottom up, by building upon the mathematically proved seL4 microkernel and its software ecosystem and trusted open-source components.

With the TRENTOS SDK, HENSOLDT Cyber provides a complete development environment that equips a developer with all the tools required for building, testing and deploying TRENTOS-based systems to the real world. The SDK contains the actual operating system (OS) source code, consisting of seL4, CAmkES and TRENTOS, but also offers a collection of additional resources designed to make developer’s work easier by increasing efficiency and reducing complexity.

Services & Trainings

This one-week course introduces the fundamental aspects of TRENTOS, a novel seL4-based secure embedded operating system developed by HENSOLDT Cyber. The course is split in a lecture part, which covers the theoretical background including the basic aspects of seL4 and CAmkES, and a practical part that provides a basic case in order to teach participants how to create their very first TRENTOS application.

HENSOLDT Cyber's TRENTOS training has received interim endorsement as seL4 training by the seL4 Foundation as a Trusted Service Provider for seL4-based systems and for our Training offering for seL4. TRENTOS has received interim endorsement as a seL4 product as well.

With TRENTOS, HENSOLDT Cyber takes the next logical step

– developing a novel secure embedded OS on top of the proven seL4 ecosystem. It alleviates the entry to the quite complex area of developing secure embedded systems by abstraction.

Now, developers can fully focus on creating secure applications without having to worry about lower-level details and the underlying architecture.


See what our experts say

"Taking the first step in seL4 development can be quite challenging. TRENTOS provides you with the basic features necessary for security critical applications in embedded environments, so you don’t need to dive deep into microkernel architectures. 

Hence you can focus on creating your applications and systems with security by design. It leverages the statements of the seL4s formal proof to a systems level"

Sascha Kegreiß, CTO at HENSOLDT Cyber

"TRENTOS leverages seL4’s mathematically proved security enforcement while presenting a higher-level interface that is easier to understand and use than seL4’s low-level mechanisms. 

TRENTOS provides the basic functionality required by security-critical systems with a minimal trusted computing base, protected by seL4"

Gernot Heiser, Chief Scientist Software at HENSOLDT Cyber


"By building upon the proven seL4 ecosystem, TRENTOS consequently relies on trusted open source software components, which allow the creation of an operating system that perceives security as an integral part right from the start. 

TRENTOS alleviates the entry to the quite complex area of developing secure embedded systems by abstraction, letting developers fully focus on creating secure applications without having to worry about lower level details of the underlying architecture."

Sebastian Eckl, Software Engineer at 



Explore the security advantages of the seL4 microkernel firsthand through our operating system TRENTOS

For further inquiries please

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HENSOLDT Cyber stands for Secure IT instead of IT security. If you would like to receive more information about our technology and products, please visit our company site.


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HENSOLDT Cyber GmbH I Willy-Messerschmitt-Straße 3

82024 Taufkirchen Germany