Post-quantum defaults

[Bruce Walzer]

On Tue Apr 7 00:59:44 CEST 2026, Bruce Walzer via Gnupg-users wrote:

> There seem to be two papers that have sparked the recent
> excitement. One involves boring old superconducting qubits. AFAIK,
> it assumes a significant improvement in noise performance to
> work. So the fact that it uses less qubits isn't very interesting in
> the absence of increased noise performance. Impossible is still
> impossible.

> The other one involves something called neutral atoms. This
> technology has better noise performance. But it is a different
> technology. It appears that we don't know how to run a relevant
> algorithm on it at this time in a useful way. The paper refers to
> "engineering challenges". So I think this is the one to pay
> attention to in the next few months. We need to wait for comments
> from knowledgeable critics.

Dunno how knowledgeable this this critic that posted on Twitter is:

* https://nitter.net/bergealex4/status/2038908698915926516

... but they do bring up a relevent point about entanglement performance from the neutral atom technology. The paper says:

> By rastering the beam dynamically to increase the active duty cycle,
> the number of atoms that can be addressed and entangled at high
> fidelity could thus be directly increased by three orders of
> magnitude. Although integrating these capabilities at larger scales
> requires substantial development effort, they appear to be mutually
> compatible, such that an appropriately designed architecture could
> realize the functionality illustrated in Fig. 1a.

For superconducting qubits the noise performance needs to be increased
1-2 orders of magnetite to enter the realm of the possible. Dunno if
entanglement capability comes in on top of that to do Shor's.

So both papers describe an impossible world and don't help for
planning a post quantum encryption rollout. That would change in the
event someone invents suitable hardware based on some fundamentual
breaktrhough in physics. Then we would have some idea of the extra effort required on the algorithm side of the problem. 

Bruce