Welcome to QuTech's Quantum Network Explorer QKD challenge!

In this challenge you will have the possibility to implement your own QKD protocol and test it against an eavesdropper. Will you be able to detect an eavesdropper trying to listen in on your communications?

The rest of this README will take you through setting up your environment. For the tasks involved in this challenge, please see CHALLENGE.md.

If you are entirely new to quantum communication, please head over to the Quantum Network Explorer learning section and explore some pre-built applications or read up on the basics on the knowledge base.

For a basic introduction to Quantum Key Distribution, you can watch this QuTech Academy video.

Firstly, you will need Python installed on your machine for this challenge.

CRITICAL: USE A PYTHON VERSION <= 3.9 --- DO NOT USE PYTHON 3.10.

The quantum network simulator, NetSquid, has not been updated for Python 3.10 yet.

Before continuing, it is recommended that you set up and work in a Python Virtual Environment. For more information, please see this tutorial. In addition to isolating your environment, it will also allow you to use an older Python version without having to uninstall Python 3.10 (if you have it). It is assumed from this point, that you are running in a Python virtual environment. The instructions should still work without a virtual environment, but they might be more difficult to debug in case something goes wrong.

In order to make use of QuTech's discrete simulator for quantum networks, NetSquid, you will need to first agree to the terms of service by registering on the community forum. Please register by following this link. Write down your chosen username and password, you will need it in a moment.

First, you will need to clone this repository onto your computer. Please choose a suitable directory and run git clone with the GitHub link for this repository.

Next, you need to install SquidASM and the Quantum Network Explorer Application Development Kit (QNE-ADK). SquidASM is a NetQASM application processor built on top of the NetSquid quantum network simulator. You will use SquidASM to simulate your quantum network applications. The QNE-ADK offers a CLI interface for creating and running network experiments.

You can install both easily by running the following command from inside this repository after having cloned it (you will be prompted for your username and password that you chose earlier):

Run the following commands:

pip3 install -e "git+https://github.com/QuTech-Delft/qne-adk.git@a125b2d27f1e5fef2822329cf824b18e22e9d00e#egg=qne-adk"
pip3 install squidasm==0.8.4 --extra-index-url https://pypi.netsquid.org

You can verify the QNE ADK installation by running

qne --help

The next few sections will take you step by step on how to create and run application using the QNE ADK and SquidASM. For more information, please refer to the QNE-ADK guide. The QNE-ADK guide contains more detailed information and instructions on what is going on.

First, you need to create the application which contains the source code directory. To create the application directory, please run

qne application create qkd alice bob

This will create an application called qkd consisting of two programs, alice and bob, that will run on separate nodes. You can choose the application name, as well as the node names, to be whatever you wish, but your final submission needs to use qkd for the application name and alice and bob for the programs in order for the autograder to work.

You will mainly be writing code in qkd/src/app_alice.py and qkd/src/app_bob.py. For more information about the directory structure and how to configure the application, please refer to the application configuration guide. For more information on options available through the CLI, please consult qne application --help.

An application is not very useful if it does not run on some network as part of some kind of experiment. To run your application, you first need to create an experiment. To create an experiment, please run

qne experiment create exp qkd randstad

This creates an experiment called exp running your application called qkd on a pre-configured network called randstad. The Randstad is an area in the Netherlands consisting primarily of the four largest Dutch cities (Amsterdam, Rotterdam, The Hague, and Utrecht) and their surroundings. The details of the available networks, their nodes, and available channels can be found in the Randstad section on the network configuration page.

Note that the experiment names you use don't matter, unlike the application names, because the autograder will create its own experiments to verify your solution.

For more information about the directory structure and how to configure the application, please refer to the experiment configuration guide. For more information on options available through the CLI, please consult qne experiment --help.

Once you have an experiment created you can run it with

qne experiment run exp --timeout 30

Where you replace exp with the experiment name you chose earlier, if it's different from exp.

You can view the results of the experiment in exp/results/processed.json or by running qne experiment results exp --show (replacing exp with your experiment name if necessary). The results found at the top under round_result contain the contents of the dictionaries returns by app_alice.py and app_bob.py.

Once created you can rerun the experiment as many times as you wish.

DO NOT MODIFY the source files in the experiment directory. They are overwritten with every experiment run.

If you need to change the application code, make sure you change it in the application directory qkd/src. These files will be copied over to the experiment directory with every run.

To configure your experiment, you can modify the experiment.json file in your experiment directory. You will want to pay particular attention to the roles entry which identify the nodes where your alice and bob applications are run. By default this will be amsterdam and leiden for the randstad network. Therefore, the parameters of the relevant quantum channel for your application are in the entry identified by the slug amsterdam-leiden. You will need to modify this channel's fidelity in the challenge.

Please see experiment configuration for more details on how to use this file.

It may be useful to go through an application example to see how to write a quantum network application. To see such an example, please see this application example.

As you will have seen from the application example, applications are written using the NetQASM SDK. For detailed documentation about the available functionality, please see the documentation page, and in particular netqasm.sdk.

You may also want to read the paper introducing NetQASM.