Led by the Croatian Academic and Research Network – CARNET, and with scientific leadership from RBI, the CroQCI project brings together key national research and academic institutions, higher education bodies, public institutions, and enterprises, with the ultimate goal of strengthening national cybersecurity in line with cutting-edge scientific advances.
A National Consortium, Built to European Standards
At the center of today’s event was the joint team from RBI and OIV, which designed, developed, and manufactured the components and systems that enable quantum key distribution (QKD), the secure generation and distribution of cryptographic keys. These systems are already operating on OIV's optical fiber network in Zagreb.
In an era of mounting cyber threats, quantum communication offers a solution that relies not on computing power or algorithms, but on the immutable laws of quantum physics. This represents a new benchmark for digital sovereignty and system resilience: any attempt to intercept communication can be detected, and key compromise can be prevented at the outset. Today's demonstration proves that Croatia, thanks to the CroQCI consortium, RBI, and OIV, is not waiting for technology from abroad, but is building it at home—sovereignly, with local knowledge and technology.
The media demonstration showcased three pillars of the future quantum network. First, quantum receivers with optical modules and photon detectors, including the integration of superconducting photon detectors, crucial for registering highly sensitive quantum signals. Second, a quantum operator system that generates entangled photon pairs—the foundation of today’s most secure practical implementation of quantum communication. Third, hardware encryptors based on FPGA chips, which encrypt messages using quantum-generated keys. Together, these confirm that quantum communication is no longer confined to the lab, but is operational in practice, on the optical network of CroQCI partners in Zagreb.
Sovereignty as a Standard: Safer Links, More Resilient Systems
This technology is significant on multiple levels, offering a nationally sovereign approach to secure communication and laying the groundwork for further development of quantum networks and systems in Croatia.
“These components were developed in Croatia at RBI, using our own expertise and resources. This is yet another testament to how RBI, through excellence and collaboration, remains a key player in shaping Croatia’s scientific and technological future. Through the CroQCI project, RBI will continue to actively support and lead the development of quantum communication in Croatia, while strengthening research in this field. The advancement of these efforts will be further supported by the new infrastructure we are building as part of the capital O-ZIP project,” said Dr. David M. Smith, Director of RBI.
“Our goal is simple yet strategically critical: to build a domestic, sovereign, and resilient communication network that relies on the laws of quantum physics. not computing power, for securing connections, thereby elevating the national level of cybersecurity. In the coming period, we will focus on integrating Croatia’s quantum infrastructure with the European quantum network, combining terrestrial and satellite technologies. Today’s demonstration shows that we’re not in a phase of promises, but in a phase of delivery. The Croatian quantum connection is operational, and the multidisciplinary knowledge we've assembled allows us to expand this infrastructure across Croatia and into the EU,” stated Bojan Schmidt, CroQCI Project Lead at CARNET.
Proven Technology With Global Roots
Dr. Martin Lončarić, Scientific Director of the CroQCI project and member of RBI’s Laboratory for Photonics and Quantum Optics, linked today’s milestone to previous international successes:
“Our approach builds on knowledge and technologies we've already applied internationally, such as the creation of the world’s first entanglement-based quantum communication network in Bristol in 2019, and the demonstration of the first quantum communication between Italy, Slovenia, and Croatia during the 2021 G20 summit. The technology we’re presenting today is based on quantum entanglement, which enables a level of data transmission security that classical systems cannot match. We’re proud to say that the entire system—from photon source to receiver—was developed and built in Croatia.”
OIV, the industrial partner in the project, emphasized the infrastructure is already in place. “OIV developed encryptors that secure messages using quantum-generated keys, based on state-of-the-art FPGA programmable chips. We also implemented the optical infrastructure linking key institutions in Zagreb, which was a crucial prerequisite for establishing the national quantum communication network. This marks a significant step forward for our communication security,” said Duje Gašperov, Senior Specialist for New Technologies at OIV.
The photons are ready. So are we.
CroQCI is a strategic national project under the pan-European EuroQCI initiative, aiming to establish ground-based and satellite-enabled quantum communication infrastructure that ensures ultra-secure information transmission in Croatia, and connects it to the wider European network.
The project is led by a consortium comprising: Croatian Academic and Research Network – CARNET (Project Lead), Ruđer Bošković Institute (Scientific Lead), University of Zagreb - University Computing Centre (SRCE), Institute of Physics (IFZ), Faculty of Electrical Engineering and Computing (FER), Faculty of Transport and Traffic Sciences (FPZ), OIV – digital signals and networks, and the Office of the National Security Council (UVNS).
With a total value of €9.9 million, CroQCI is co-financed by the European Union through the Digital Europe Programme (DEP) and the National Recovery and Resilience Plan (NPOO). The project runs from January 1, 2023, to June 30, 2026, with the ultimate goal of strengthening national cybersecurity in line with the latest scientific developments.
About the CroQCI Project
Croatian Quantum Communication Infrastructure – CroQCI is a strategic national project focused on developing and implementing an ultra-secure data transmission network based on quantum physics principles. It is part of the broader pan-European initiative EuroQCI (European Quantum Communication Infrastructure), with the goal of building a resilient, domestic infrastructure for quantum-secured communication between key national, scientific, and infrastructure institutions.
The project aims to establish a comprehensive quantum communication infrastructure (QCI), encompassing both terrestrial and satellite components, to ensure ultra-secure data transmission within Croatia and enable integration with communication systems across the European Union.
CroQCI is coordinated by CARNET, with scientific leadership from the Ruđer Bošković Institute, and includes partners such as the University Computing Centre (SRCE), Institute of Physics (IFZ), Faculty of Electrical Engineering and Computing (FER), Faculty of Transport and Traffic Sciences (FPZ), OIV, and the Office of the National Security Council (UVNS).
The €9.9 million project is co-funded by the European Union through the Digital Europe Programme (DEP) and the National Recovery and Resilience Plan (NPOO), running from January 1, 2023, to June 30, 2026.
