From April 21–24, 2026, the National Cyber and Information Security Agency (NÚKIB) participated in the prestigious international cyber exercise Locked Shields 2026, which is considered the largest and most comprehensive cyber defense exercise in the world. The exercise is organized annually by the NATO Cooperative Cyber Defence Centre of Excellence (CCDCOE). The Polish-Czech team ultimately secured fourth place among sixteen teams.

The main objective of the Locked Shields 2026 exercise was to strengthen and further develop the cyber defense capabilities of the participating nations, promote international partnerships and cooperation between the public and private sectors, and foster innovation in the field of cybersecurity.

The exercise simulated a large-scale, realistic cyber conflict in real time and tested the participants’ technical, operational, and strategic capabilities. Teams were under significant decision-making pressure and had to respond to rapidly evolving situations, unexpected threats, and complex crisis scenarios. The inclusion of legal and communications teams, which are an integral part of crisis management, further enhances the realism of the exercise.

“Today, cyberattacks threaten not only the availability, confidentiality, and integrity of data, but also the functioning of essential services on which society depends. Cybersecurity exercises therefore simulate realistic crisis situations in which participants test not only their technical defenses but also their ability to make decisions under pressure and coordinate actions with other partners. This allows us to identify vulnerabilities in a timely manner and systematically increase the resilience of the state and society against cyber threats,” said Irena Adler Pavelková, Director of the Training and Education Department at NÚKIB.

Approximately 4,000 experts from 40 countries around the world participated in this year’s exercise. The competing teams were composed of participants from at least two different countries. The Czech Republic formed a joint team with Poland. A total of 16 international teams participated in the exercise, operating remotely from their home countries.

The fictional scenario for the Locked Shields exercise is designed to reflect current global security challenges as accurately as possible. It included elements of geopolitical tension, such as violations of international borders and state sovereignty, the construction of artificial islands, and coordinated cyberattacks that impacted state operations and public trust. This year, the organizers also incorporated the issue of election security into the scenario.

“The Locked Shields exercise is a great opportunity for community building and fostering cooperation across the academic, public, and private sectors. I would like to thank all our partners, thanks to whom this unique format can continue to exist,” said Lukáš Kintr, Director of NÚKIB, in a statement to CZ DEFENCE.

The exercise focuses on protecting vital services and critical infrastructure, which are essential for the functioning of modern societies, as well as on ensuring the operation of military infrastructure. The exercise involved partners without whom it would not have been possible to carry it out in its current form: NIX.CZ, Progress/Flowmon and ALEF, the Brno Technology Park, and CETIN, which provided connectivity.