**What is a quantum network?**

Establishing secure cryptographic keys through an untrusted network is one of the most fundamental cryptographic tasks. While the use of popular public-key approaches that are based on complex mathematical problems and assumptions on the computational power of eavesdropper prevail, such solutions are theoretically breakable considering the continuous growth of computational power. On the other hand, quantum key distribution (QKD) represents a new generation of security solutions that rely on the laws of physics to provide information-secure cryptographic keys.

There are different approaches of integrating quantum technology into existing network infrastructures which comprise centralized or distributed network management, direct optical or free line of sight links, terrestrial or satellite quantum communications, channel integration over the same fiber, and more. A network that relies on quantum cryptography principles to ensure secure communication is often referred to as a QKD or quantum network and it is mainly evaluated considering:

- the average amount of cryptographic keys established in a unit of time,
- the length of implemented QKD links,
- key material management,
- network utilization and scalability.

**OPENQKD **project and its partner in Sarajevo – the University of Sarajevo located in Bosnia and Herzegovina work on a quantum network simulator (QKDNetSim) which allows simulating various ways of integrating quantum technology into existing telecommunication networks. QKDNetSim enables to assess the practical feasibility and foresee difficulties in the implementation of theoretical QKD network approaches.