On August 5, 2021, during the G20 Digital Ministers’ Meeting in Trieste, Italy, the first public demonstration of intergovernmental quantum communication between three countries took place, connecting Italy, Slovenia, and Croatia. An encrypted audio-video communication was established between nodes in Trieste, Ljubljana, and Rijeka using quantum key distribution (QKD) technology. According to the Croatian Ministry of Foreign and European Affairs, the Croatian side also demonstrated “quantum-enhanced cryptography” on the Rijeka-to-Zagreb link for the first time in public.
On the Croatian side, the demonstration was led by Dr. Mario Stipčević and Dr. Martin Lončarić from the Ruđer Bošković Institute (RBI), with support from the Faculty of Transport and Traffic Sciences at the University of Zagreb and telecom company OIV. The 100.5-kilometer quantum link between Trieste and Rijeka used a dedicated fiber-optic connection. The quantum-enhanced cryptography device used on the Rijeka-Zagreb link was developed jointly by the PCE Marine Electronic Center in Split and RBI.
Multiple Croatian government bodies supported the event, including the Ministry of Foreign and European Affairs, the Ministry of Science and Education, the Ministry of the Sea, Transport and Infrastructure, and the Ministry of Defense. The Croatian Science Foundation also provided project funding.