Date: 14. 12. 2022.

The confirmation of the success of the first public demonstration of the inter-European quantum communication network, which was established during the G20 ministerial meeting in Trieste by a group of scientists who achieved encrypted communication between Italy, Slovenia and Croatia, was just published by the respected scientific journal Advanced Quantum Technologies. This paper is a scientific confirmation of the achievement of quantum communication between three different countries for the first time in the world, in which history was written by Croatian scientists and experts.

The network was created thanks to the efforts of teams from the University of Trieste, the Italian National Institute of Optics (CNR-INO), the Technical University of Denmark, the Faculty of Mathematics and Physics of the University of Ljubljana, while in Croatia the project was led by Mario Stipčević, Ph.D.  and Martin Lončarić, Ph.D.  from the Ruđer Bošković Institute (IRB), prof. Dragan Peraković, Ph.D. and Ivan Cvitić, Ph.D. from the Faculty of Transport Sciences of the University of Zagreb and the company Odasiljači i veze (OIV).

"With the successful realization of this venture, we laid the foundations for the implementation of quantum infrastructure in the Republic of Croatia (RO), while at the level of the European Union (EU), this experiment laid the foundation stone for a wider European quantum communication network - EuroQCI, within the framework of the main EU programs - and Digital Europe and the Connect Europe Facility program,'' says Dr. sc. Mario Stipčević, head of the Laboratory for Photonics and Quantum Optics at IRB, one of the coordinators of the demonstration in Croatia and co-author of the paper.


Absolute security of quantum communication

The amount of internet traffic is growing rapidly from year to year, but unfortunately the intensity of cyber attacks on IT infrastructure is growing even faster. The security of state institutions, industries and citizens is threatened by such attacks, so the realization of a quantum network that would guarantee secure communication has become one of the most important strategic goals of countries around the world.

Thanks to the quantum encryption that works through the exchange of photons, which enables the immediate detection of hacking attempts, quantum communication achieves absolute security.

"Suppose someone tries to intercept this type of communication. In that case, he is instantly detected even before he got hold of the data he wanted to steal, and this is exactly what guarantees the maximum protection of data and communication," explains Dr. sc. Martin Lončarić, co-author of the paper, who, together with Dr. Stipčević, coordinated these activities in Croatia. dr. Lončarić further pointed out that precisely for the purpose of protecting its own security and technological independence, the European Commission decided to build a network of ultra-secure 'quantum Internet' in the next ten years within the framework of the European Quantum Infrastructure program - EuroQCI, to which Croatia was one of the first to join.

EuroQCI, as one of the main pillars of the new EU cyber security strategy for the coming decades, will improve European digital sovereignty and industrial competitiveness.

The establishment of a quantum network between three different countries, Italy, Slovenia and Croatia - which is described in this paper - is a forerunner of the future EuroQCI. The established network stably connected Trieste with Rijeka via a dedicated 100-km optical connection, and with Ljubljana via a reliable node in Postojna. Finally, the network was used for the world's first public demonstration of quantum communication, on August 5, 2021, in Trieste, at the meeting of the member countries of the G20 group.

"The described experimental results, as well as the interest in one of the most important events in international politics, show the maturity of quantum communication technology, putting it in the spotlight for consumer applications in the near future," concludes Dr. sc. Mario Stipcevic.

The OIV points out that their participation in 2021 in this groundbreaking technological step towards the establishment of an infrastructure for international quantum communication happened opportunely in the year when the OIV marked two great anniversaries - the 95th anniversary of the commissioning of the first radio station and the 65th anniversary transmission of the television signal in Croatia.

Together with the Croatian company OIV, the technical implementation was carried out by QTI srl – a spin-off of CNR-INO, with the support of TIM, Sparkle, Telekom Slovenije, Stelkom and Lightnet, which provided fibers and optical infrastructure. In Croatia, the implementation of this experiment was supported by the Ministry of Foreign and European Affairs, the Ministry of Science and Education (MZO), the Ministry of the Sea, Transport and Infrastructure, the Ministry of Defense and the Alan Agency, as well as HRZZ projects no. IPS-2020-01-2616 and MZO no. KK.