The light side of quantum – assessing the benefits and risks of quantum computers

A paper with the above title was recently published in the Arxiv: https://arxiv.org/pdf/2401.16317.pdf. This paper was written by a distinguished group of scientists, from Computer Science, Cybersecurity and Physics. It presents a thorough assessment of the benefits (aka the light side of Quantum) and the risks (aka the dark side of Quantum) of quantum computers.

This paper is a must-read for anybody wanting to go beyond the hype of the quantum computer and learn from the very people involved in its development. In addition, it is a refreshing example of a true collaboration between people from different fields, away from some one-sided position papers, which were published by several security agencies, such as the NSA, NCSC and more recently by a group of four European agencies. Admittedly, this paper is rather involved, with graphs and some mathematical formulas, but most of it is accessible to a lay person. If you wish to understand the status of the quantum computer, the effort is well worth it.

The main conclusions of the paper are twofold:

1. A quantum computer with economically viable applications (the light side) will be available before a cryptographically relevant one, which will break our existing cybersecurity infrastructure (the dark side). This good news is conveyed in the title of this note.
2. Nevertheless, preparing for the arrival of the latter is necessary today. Because of the so-called harvest now – decrypt later attack and of the migration time required to achieve quantum-safe security, we need to start the migration today. Fortunately, solutions are being developed. Some can already be implemented. Post-Quantum Cryptography (PQC), which replaces our existing asymmetric cryptographic algorithms by new ones resistant to the quantum threat can be deployed and should be used to protect most of our digital infrastructures. It should be complemented by quantum technologies, such as Quantum Key Distribution (QKD) for protecting long-lived information and Quantum Random Number Generators (QRNGs) for improving key generation in all cryptographic applications.

This is the approach we have been advocating at ID Quantique. The security of our future ubiquitous IT infrastructure should make use of all existing tools, both classical and quantum. This will ensure the continuing primacy of the light side of quantum with respect to its dark side.