Open QKD Network



Technological advances are bringing large-scale quantum computers closer to reality. While they will bring great benefit to society, they will also undermine some of the key cryptographic pillars of cybersecurity. It is thus imperative that the cryptographic underpinnings of cybersecurity are made resistant to quantum attacks before quantum computers threaten them. Quantum-safe cryptography includes conventional “post-quantum” cryptography (PQC) algorithms (sometimes referred to as “quantum-resistant” algorithms (QRA)) and quantum key distribution (QKD).

The long complex path to making our cyber systems safe in an era with quantum computers requires planning and collaboration amongst many stakeholders. Part of this plan is mapping out the role for QKD in future cryptographic infrastructure, and this initiative is a key step in this regard.

The project also lays the foundation for further development of a QKD-based key establishment system to work alongside conventional PQC-based cryptographic tools. Together, QKD and PQC will provide the foundations for cryptography in an era with quantum computers.

System Architecture

In this project, we outline a layered framework (see the figure below) for incorporating QKD into conventional communication systems. This framework accommodates different physical approaches to implementing QKD and advances in quantum communication technologies that will continue to improve the performance and reduce the cost of QKD systems. This framework will accommodate a variety of approaches to turning point-to-point QKD links into a network level QKD service. A key management service (KMS) layer will interface with the QKD network layer (QNL) in order to provide keys to the applications or users at the Hosts Layer. Changes and advances can proceed in any of the four layers without impacting the functioning of the other three layers.

Open Source Software Implementation

The project team has implemented the KMS and QNL layers as well as a simulator of the QLL in software. The source code and documentation are publicly available at here, and the open source project is under active maintenance.

Researchers on QKD technology are welcome to download and use the software system to integrate with their QKD devices and do demonstrations to promote their work.

Developers and researchers of applications that may benefit from quantum key agreement are welcome to download and use the software system (with our QLL simulator and/or other quantum hardware links they may have available) to prepare for and test the integration of QKD keys into their applications. It is important to note that the design and software testing may be done even without QKD hardware at this point. Systems designed with the KMS as a key agreement option may benefit from available QKD systems at any point in the future that they become available.

Photo of the Four-Layer Architecture of the Integrated QKD and Conventional Communication Networks
Figure 1 the Four-Layer Architecture of the Integrated QKD and Conventional Communication Networks

Project Team

The project is conducted by a multidisciplinary team at the Institute of Quantum Computing (IQC), the University of Waterloo, including mathematicians, physicists, architects, engineers and developers.

The project team is led by:

Current team members, (ordered by last name) include:

  • Dr. Xinhua Ling, System Architect/QNL Designer/Project Manager
  • Kaiduan Xie, Software Developer

Past project team members (ordered by last name) include:

  • Dr. Jean-Phillipe Bourgoin, QLL Researcher
  • Dr. Brendon Higgins, QLL Researcher
  • Professor Thomas Jennewein, Lead of QLL
  • Shravan Mishra, Software Developer
  • Dr. Peter Tysowski, KMS Designer


  1. “Quantum Key Distribution Integration Scope and Requirements Study”, NRC Report, Aug. 2016
  2. “Quantum Key Distribution Integration Project”, NRC Report, May 2017, June 2018
  3. “The Engineering of a Scalable Multi-Site Communications System Utilizing Quantum Key Distribution (QKD)”, Quantum Science and Technology 3, no. 2 (2018): 024001, arXiv:1712.02617v1


Please send your query by email to: Michele dot Mosca at uwaterloo dot ca


The project is funded by National Research Council, Canada, 2016-2019.