Is it?

Your reasoning relies on this being true:

> [CRQCs] will be slow, expensive, and power hungry for at least a decade

How could you know that? What if it was 5 years? 1 year? 6 months?

I predict there will be an insane global pivot once Q-day arrives. No nation wants to invest billions in science fiction. Every nation wants to invest billions in a practical reality of being able to read everyone's secrets.

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adgjlsfhk1 2 hours ago | parent [-]

The absolute low end of cost of a QC is the cost of an MRI machine ~100k-400k (cost of cooling the computer to super low temps). Sure we expect QCs to get faster and cheaper over time, but putting 100% faith in the security of the PQC algorithms seems like a bad idea with no upside.

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phicoh 2 hours ago | parent | next [-]

It is the paradox of PQC: from a classical security point of view PQC cannot be trusted (except for hash-based algorithms which are not very practical). So to get something we can trust we need hybrid. However, the premise for introducing PQC in the first place is that quantum computers can break classical public key crypto, so hybrid doesn't provide any benefit over pure PQC.

Yes, the sensible thing to do is hybrid. But that does assume that either PQC cannot be broken by classical computers or that quantum computers will be rare or expensive enough that they don't break your classical public key crypto.

	▲	FiloSottile 2 hours ago \| parent [-]
		> from a classical security point of view PQC cannot be trusted [citation needed] https://words.filippo.io/crqc-timeline/#fn:lattices

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FiloSottile 2 hours ago | parent | prev [-]

We can disagree on the tradeoff, but if you see no upside, you are missing the velocity cost of the specification work, the API design, and the implementation complexity. Plus the annoying but real social cost of all the bikeshedding and bickering.