The quantum key distribution network simulator (QKDNetSim) is a simulation software for quantum key distribution with post-processing emulation support. It is develoepd as a simulation module that extends the NS-3 network simulator with QKD network functionality. The main purpose of the network simulator is to analyze different approaches to QKD network organization and to simulate networking technologies, including the integration of QKD systems into existing telecommunications networks, with a focus on network security. QKDNetSim implements the full functional Key Management System (KMS) with key-relay functionality supporting ETSI GS QKD 014 and ETSI GS QKD 004 key delivery interfaces.

Web interface

Web interface is publicly available via www.open-qkd.eu

Post-processing (key-generation)

Each QKD protocol implements a post-processing of the raw key including sifting, error estimation and reconciliation, privacy amplification, and authentication. A correlated non-symmetric series of secret bits is created during the exchange of quantum information across the quantum channel. The term “raw key” is often used to describe this resultant sequence. Instead of simulating every QKD protocol (DV-QKD, CV-QKD, entanglment-based QKD) and different approaches for post-processing (CASCADE, LDPC, Winnow and other), QKDNetSim implements post-processing application that imitates the QKD protocol of network activity. It sends data back and forth, generating network traffic similar to the QKD protocol. However, several configuration parameters are available to influence the process and tailor it to the real-world setting (i.e., generated key size, key generation rate, and traffic intensity on the public channel during post–processing).

Thus, QKDNetSim cannot simulate quantum channel operations (polarizes, detectors, gates, etc.) and external tools can be used to mimic them reliably. One of the most common tools for these needs is Qiskit, which can be easily connected to QKDNetSim in the emulation mode.

End-user applications (key-consumption)

Keys established and maintained by the QKD network are supplied to cryptographic applications on request. These applications use obtained keys to establish secure communication.

Two end-user (cryptographic) applications are implemented in QKDNetSim: QKD Application 004 (QKDApp004), which is based on ETSI QKD 004 specifications, and QKD Application 014 (QKDApp014), which is based on ETSI QKD 014. These applications can simulate how keys are used in data encryption and/or authentication procedures. Their objective is to consume keys and evaluate the overall system performance and KMS capabilities across various scenarios. They offer various configuration parameters, including encryption and/or authentication settings, data rate, packet sizes, and others based on the user’s choices. The communication can be secured by a combination of encryption and authentication algorithms, such as Advanced Encryption Standard (AES), OTP, Wegman-Carter, or SHA-512.

Emulation mode

  • Mehic, M., Dervisevic, E., Burdiak, P., Lipovac, V., Fazio, P. and Voznak, M., 2024. Emulation of quantum key distribution networks. IEEE Network, 39(1), pp.116-123. doi:10.1109/MNET.2024.3398404
  • Mehic, M., Dervisevic, E., Fazio, P. and Voznak, M., 2025. Virtual Quantum Key Distribution Network Ecosystem: The National Czech QKD Network. IEEE Network., 39(3), pp.173-179. doi:10.1109/MNET.2025.3540705

Download

The QKDNetSim (v2.0) source code is free for download from “https://github.com/QKDNetSim/qkdnetsim-v2“

Cite

  • Dervisevic, E., Voznak, M. and Mehic, M., 2024. Large-scale quantum key distribution network simulator. Journal of Optical Communications and Networking, 16(4), pp.449-462. doi: 10.1364/JOCN.503356