SSH keys, on the other hand, are authentication and would require an online Quantum Computer to break, so we have more time. Authentication is also (usually) more complicated, so there are still disagreements on what to do with the Web PKI for example. To give you a concrete target, Google, Microsoft, and CloudFlare have self-imposed deadlines of 2029 for their PQC migrations.
In practice, PQC migration means updating your software, bugging your vendors to ensure they have this on their roadmaps, and making sure your own code is flexible in respect to algorithms used.
On a separate note, I've definetly been hearing worried murmurs about "harvest and decrypt" attacks along with post-quantum TEE slightly before the GCP paper, and I definetly think it appears a couple nation states are on track for a "quantum leap" by 2030 given the rate at which I've been hearing it within my network.
Maybe the best practice here is to have one or more Boppers on your team who send out periodic notifications to update not just algos in libraries but, more importantly, make sure those updates are reflected in the damned configs.
We also really need a cultural shift where it becomes expected that, for any given app, we have something like:
$ ssh --best user@host
which does that for us. Because this is a failure mode that shouldn't even be possible for most users and cases.
The worry about "harvest and decrypt" in a 5 year timeframe is primarily from a nation state/natsec perspective.
If you are being targeted by a nation state as a line level engineer, harvest and decrypt is the least of your worries.
...8 years previously.[1]
Long, long ago in a datacenter far away, breaking 3DES used to be the province of expensive bespoke hardware owned by only the elite nation states. Today it is so trivial that the gpu in your second hand laptop can do it "at scale".
5 years ago ChatGPT was a wet dream.
We should be very conservative in our planning where future security is concerned. The only thing we can be sure of is that Murphy's Law is looking for every chance to make us look foolish.
If you have any link to trivially cracking it on your second hand laptop and doing it at scale, would be very interested.
Of course I can't find the link to whatever I read that discussed gpu accelerated des cracking now.