A very nice explainer why "if you're so worried about quantum computers, why haven't they factored 21 yet?" isn't a very convincing argument. Look at the labels of the graph, and how extremely close the various lines are for factoring 21 and 2048 bit numbers. Polynomial scaling remains polynomial, unfortunately, and by the time you can factor 21 you're almost ready to break RSA.

https://bas.westerbaan.name/notes/2026/04/02/factoring.html

Factoring is not a good benchmark to track Q-day

Homepage of dr. Bas Westerbaan, principal research engineer at Cloudflare, working on making the Internet post-quantum secure

@sophieschmieg I suspect people will listen to cryptographers and quantum-focused computer scientists on this subject with the same focus and rigor they did when they said "no, no, don't roll your own cryptography, that's a bad idea".
@sophieschmieg so when we quanting? When's quanting time?
@sophieschmieg just as clarification: not meant to make fun of you but to make fun of me and how little I understand of this topic. I always thought I'm somewhat understandable in IT stuff, but every time I try to understand quantum computing, I feel like a toddler trying to understand quantum computing
@leberschnitzel that is the billion dollar question. There is a non negligible chance of it being as early as 2029, but it might very well be several years later, we just can't ignore it being possible in 2029.
@sophieschmieg yeah, totally get that.
At work we also preparing for it and especially the certificates team is working on things.

@sophieschmieg A physicist I used to work for said quantum computing is very good right now for getting grant money to develop very nice ADC's and detector circuitry, which is useful for astronomy and particle physics.

He admitted when I pressed him that he agrees that the actual computing part is complete bunk and going nowhere.

@poleguy @sophieschmieg

I remember similar opinions in the 80s when people would bring up Reagan's "Star Wars"/SDI.

@danmcd @sophieschmieg And how do we feel those opinions aged?

@poleguy @sophieschmieg

I don't know, given I don't know what SDI money got put to what use. GPS? IF so then that's not a bad deal.

@danmcd @sophieschmieg the opinions back then were that Star Wars/SDI was science fiction and it would never work... and I think that is still true. There is no space based laser defense system and nobody sees that in the timeline, right?

The groundwork for GPS work pre-dates SDI.

@poleguy @sophieschmieg @cstross ding ding ding! 'Quantum computing' is full of the same kind of lunacy as LLMs; "it's inevitable, it's the future, ignore hitting obvious dead-ends." I would say that given the current landscape, effective communication by quantum teleportation over long distances is more likely to happen first despite the LLM-fanboy VCs shoveling money as fast as they possibly can.
@poleguy @sophieschmieg @cstross and yes, quantum teleportation is absolutely real, empirically proven, and Urbana-Champaign achieved a *94%* fidelity with indium-gallium-phosphide last year. Meaning we are getting very close to "it's a scale manufacturing problem."
@poleguy @sophieschmieg I’m reminded of the thing that goes around occasionally about how Loch Ness is a great place to be a marine biologist because you can get money from people trying to find Nessie. And in the “search” you end up doing some really cool research most people can’t do because they don’t have that sort of funding.

@sophieschmieg This articlae say, you shouldn't take factoring as a good metric to measure progress, fair enough, but then you argue, in fact it's gonna be very soon we can factor. Isn't this a contradiction? THis is not a snarky remark. Personally I think QC is a risk, like there are many others. But I think there are biger, known risks.

And the store now decrypt later stuff I think is non-sense. Storing everything is not feasible, storing select stuff means you have a problem now, because some one ass already access to select important stuff. That boils down to a quote from Adi Shamir: NSA is not a crypto breaking agency, it's a crypto evading agency,