[teravor]

    > That is possible, but given the recent 2029 timelines from large Internet providers, I think it's prudent to prepare for Q-Day even if it never arrives.

no one argues we shouldn't. you made the argument that we should abandon ECC by not doing hybrid, in my opinion it's an extremely weak argument because it assumes Q-Day will arrive. don't change goalposts.

the article you linked supports my position.

    > the fear of the quantum doomsayers is based on a completely valid observation: the internet has put nearly all of its cryptographic eggs into the single basket of the hidden subgroup problem.

    > By the time the next phase of standardization is over, we can expect to have algorithms based on at least three or four different mathematical problems. If one of the selected problems were to fall to advances in quantum or classical algorithms, there are readily-available replacements that are highly unlikely to be affected by attacks on the fallen cryptosystems.

in fact, it makes the argument (if not directly) for a concatenation of multiple schemes. I'm all for it, hybrid++.

[some_furry]

> you made the argument that we should abandon ECC by not doing hybrid,

Where did I ever make that argument? In both TFA and my previous blog post, I've made it abundantly clear that I'm pro-hybrid.

My argument is simply:

1. The claimed benefits of ECDH hybridization evaporate immediately the moment Q-Day happens. No one disputes this.

2. Harvest Now, Decrypt Later (HNDL) is the primary threat we face today during the uncertain times where we don't know if Q-Day will ever happen.

Advocating for PQ+ECC hybrids over PQ is fine. But fear-mongering about PQ in this threat model is self-defeating: Once Q-Day happens, your only source of security is PQ anyway, so if we're going to do hybrids with today's threat model in mind, PQ+PQ is the way you really want to go (and PQ+PQ+EC if you really want EC). The blog post you're commenting on says this explicitly.

I'm not anti-hybrid. I'm anti "this is an NSA ploy" bullshit. And the IETF mailing list thread I'm mentioning is stuffed with this kind of irritating conspiracy theory rhetoric. I even link to, and quote, two examples of this.

[loup-vaillant]

In your PQ safety blanket article https://soatok.blog/2026/04/13/hybrid-constructions-the-post... you make it pretty clear the reason you support hybrid is tactical, not cryptographic.

Your wording ("Once Q-Day happens") strongly suggests Q-Day will happen, like, it’s so certain you don’t even need to state it explicitly, you can just assume it will. And your references to the PQ timeline give the impression that you think it will likely happen soon.

It’s pretty clear from there that you think ECDH is now technically useless, and the only real justification for hybrid schemes (as opposed to pure PQ), is to reassure the people still unsure about the likes of ML-KEM. Sure you still do recommend going hybrid, but from what I can tell, you would have preferred a world where we go pure PQ right away.

And so would I to be honest (if ECC is a bust): one algorithm is simpler and faster than two.

[some_furry]

> In your PQ safety blanket article https://soatok.blog/2026/04/13/hybrid-constructions-the-post... you make it pretty clear the reason you support hybrid is tactical, not cryptographic.

What does it matter that my public arguments are tactical? Hybrid gets us to PQ faster, which makes progress on plugging up the HNDL risk.

> Your wording ("Once Q-Day happens") strongly suggests Q-Day will happen, like, it’s so certain you don’t even need to state it explicitly, you can just assume it will.

The literal opening section is talking about recent changes in direction from large Internet providers about quantum computing risks.

The rest of the article is predicated on "these companies' risk assessment turns out to be correct".

Separately, in https://soatok.blog/2024/09/13/e2ee-for-the-fediverse-update... I wrote more about my actual beliefs about the likelihood of Q-Day.

> It’s pretty clear from there that you think ECDH is now technically useless, and the only real justification for hybrid schemes (as opposed to pure PQ), is to reassure the people still unsure about the likes of ML-KEM. Sure you still do recommend going hybrid, but from what I can tell, you would have preferred a world where we go pure PQ right away.

You are extrapolating from the subsidiary clause of an if statement whose truth value I do not claim to know.

> And so would I to be honest (if ECC is a bust): one algorithm is simpler and faster than two.

Sure.

[loup-vaillant]

> recent changes in direction from large Internet providers about quantum computing risks.

Do we have reason to suspect Google and Cloudflare have inside knowledge about quantum computers? To me this is more about the end of the NIST contest, and that one has no bearing on actual advances in quantum computing.

> The rest of the article is predicated on "these companies' risk assessment turns out to be correct".

Err, where did you wrote that? I can’t find it in your last two articles.

> You are extrapolating from […]

I exptrapolate mostly from this:

"I generally prefer hybrid KEMs–not out of any practical concern over ML-KEM’s security (or any other PQ KEMs, generally), but for reasons I’ll explain later in this blog post."

And this:

"Hybrid KEMs are an easier sell to people who are not cryptography experts than pure post-quantum KEMs for reasons that are mostly related to psychological safety than cryptographic safety."

https://soatok.blog/2026/04/13/hybrid-constructions-the-post...

Sorry if I’m misinterpreting, but as you can see I’m not the only one.

---

Anyway, good article on threat models.

[esseph]

> Do we have reason to suspect Google and Cloudflare have inside knowledge about quantum computers?

Yes.

Both have internal global security orgs that are constantly communicating with other large companies and governments. If they are accelerating (as are others), it is a signal.

The reliability of that signal is up to the reader to determine.

https://www.microsoft.com/en-us/security/blog/2026/06/30/mic...

[loup-vaillant]

> Advances in quantum research and development have shifted the risk horizon. We believe cryptographically relevant quantum computers could arrive sooner than previously expected

Aaand, there’s no citation, no reference or link for further reading, no justification for the claim. Not the most reliable signal.

[some_furry]

> Err, where did you wrote that? I can’t find it in your last two articles.

Just now. In an HN comment.

I write in conversational English. I'm not always going to meticulously write everything like a formal argument might.

If you didn't understand that what I wrote later in a blog post was predicated on an assumption established in the intro, but would have if I wrote an explicit transitional sentence, that's useful feedback. But if you're treating an informal blog post like a court filing, you might be setting yourself up for disappointment.

[loup-vaillant]

> I write in conversational English.

Fair enough.

When I write an article (and to a lesser extent even a comment like here), I tend to agonise over every sentence. I’m guessing I’m kinda assuming others do the same. Except of course they don’t.

[tux3]

>Once Q-Day happens, your only source of security is PQ anyway, so if we're going to do hybrids with today's threat model in mind, PQ+PQ is the way you really want to go

I want to broadly agree but I still can't resist arguing :)

EC is really cheap on the CPU and I trust that libsodium's X25519 is implemented pretty solidly. After Q day, the $ price to break EC is still not negligible.

Whereas PQ+PQ is really expensive. I'm anti PQ+PQ hybrid just on cost. PQ+EC is practically free and still inflicts $'s on attackers after Q day (attacks do get cheaper and you discard the EC at some point, but practically I don't see EC as instantly worthless).

[loup-vaillant]

I’ve seen arguments that PQ algorithms are easier to implement correctly than ECDH, thus reducing that risk. I’d have to try it myself to really asses that, but for now I believe them. I’d say the real cost is performance.

[some_furry]

ML-KEM is faster than X25519. The only performance downside is public key/ciphertext size. https://quantumsecuritydefence.com/quantum-news/ml-kem-vs-x2...

[yardstick]

I’m a passive observer on the same list and have been for at least several years. I don’t plan to comment on the WGLC currently going on… but I will be so extremely happy once the subject is done with.

It’s like watching a cybersecurity version of Dawsons Creek or The Young and the Restless or… Jerry Springer?! Insane

[teravor]

in that case my mistake. i always assumed that the `NSA ploy` was strategic bullshit, the sort of thing you say to get support from NSA haters.

it wouldn't even occur to me that someone would take time addressing it without being one of those anti-hybrid people.