Chasing Cyber - #23 - Europe Grumbles
Cyber agencies publish a damning report about QKD
Welcome to the 23rd edition! This week was dominated by a blistering report on QKD from European cyber agencies.
I have a few thoughts on this topic, which I’ve split into two posts below. As a reminder, this newsletter is a concatenation of my future LinkedIn posts, which sometimes means I split large topics into multiple pieces.
I’d love to hear your replies on this QKD topic. I suspect it will divide Chasing Cyber readers!
Finally, I apologise for the broken link in my last newsletter. The German BSI website doesn’t work properly when I link to it from my emails. To view the BSI report, check out the web version of the last edition, where the link works correctly.
After the Hype Comes the Storm
Yikes! Who spat in their bean curd? Quantum key distribution (QKD) gets slammed in the latest assessment from European governments.
The joint report from the French, German, Swedish, and Dutch governments is highly critical of QKD and strongly advocates for post-quantum cryptography or symmetric key distribution.
The mere existence of this report demonstrates a big challenge in the quantum cybersecurity industry. Too many voices still preach “perfect” or “unhackable” quantum solutions. While this attracts commercial success (to some degree), it forces government agencies to put our hit pieces like this one.
Let’s hope these negative reports don't squash a useful technology in its infancy. It reminds me of how the UK government failed to launch a digital ID system because they positioned it as a solution to terrorism. Had they pitched it as a cheap, wallet-sized passport, we may have had a different outcome.
I firmly believe QKD has a role to play in the future of cybersecurity. But right now, it needs support from governments and not public criticism. And yet, I struggle to blame these agencies for their report, as they've been forced to respond to the hype in the industry.
The report itself is very one-sided and overlooks significant challenges for both post-quantum algorithms and symmetric key distribution. But the criticism levelled at QKD is mostly fair. In my next post (below), I’ll break that down and analyse it.
Meanwhile, you can read the report here: https://cyber.gouv.fr/actualites/uses-and-limits-quantum-key-distribution.
P.S. If “spat in your bean curd” had you confused, watch Disney's Mulan.
Part Dieu – What’s Their Bœuf with QKD?
As mentioned above, the recent statement from European cyber agencies was highly critical of quantum key distribution (QKD). Here are the main challenges they pointed out:
Denial of Service
QKD systems only work correctly if there are no eavesdroppers on the line. This is one of the great strengths of QKD, but it is also a great weakness. A persistent eavesdropper can prevent any keys from being distributed.
Bandwidth Issues
QKD systems don't have enough bandwidth to support the distribution of one-time pads. Therefore, QKD systems are used to distribute cryptographic keys.
This means an unconditionally secure system (QKD) is used to distribute keys that will be used in systems that are not unconditionally secure. The report claims this weakens the overall benefit of QKD.
Lack of Protocol Standardisation
There has been no equivalent to the NIST PQC standardisation process applied to QKD. Of course, there are several popular schemes in the literature, e.g. BB84, but these have not been subjected to a formal standardisation process.
The report also criticises the lack of security proofs available for practical QKD protocols.
Limited Device Certification
Security devices are usually certified before being used in production. For instance, hardware security modules are usually FIPS 140-3 certified.
The report complains that there are only very limited certification schemes in place at the moment. Although, ironically, the German BSI is involved in such as scheme (and co-authored this QKD report).
Conclusions
Overall, much of the criticism in the report is fair. My main objection would be to the comments around bandwidth. They seem to imply there is no value in unconditional security in the distribution of keys, which doesn't feel right to me.
I believe many of these QKD challenges can be rectified with time. If we can control the hype around QKD and let it mature naturally, then it will become a valuable tool in the security toolbox.
It's a shame the agencies felt the need to put this piece out, but I agree with the fundamental recommendation – adopt PQC as a near-term solution.
Again, here's a link to the full report: https://cyber.gouv.fr/actualites/uses-and-limits-quantum-key-distribution.