> The first—which they say is a sort of stage 0 because it does not describe a true quantum internet—is a network that enables users to establish a common encryption key, so that they can share their (classical) data securely. The quantum physics occurs only behind the scenes: the service provider uses it to create the key. But the provider also knows the key, which means that users have to trust it.

I don't like where this is going.

> In stage 1, users will start getting into the quantum game, in which a sender creates quantum states, typically for photons.

Okay, it's going exactly where I thought I was going!

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At the risk of falling victim to the Gell-Mann effect, I'm going to call bullshit on this article.

It's overwhelmingly likely that quantum cryptography will not be the next iteration of network security technology in the real world. Rather, the focus is on what's called post-quantum cryptography. Despite what you might think, these are not two points on a timeline.

Post-quantum cryptography refers to asymmetric cryptography features that are secure even in the presence of practical quantum computers. It's not a stage that exists after quantum cryptography. There's no "intermediate" stage in which we use quantum physics itself for encryption.

There will likely be a transition, wherein today's elliptic curve cryptosystems are used in addition to a post-quantum cryptosystem (e.g. ECDH + RLWE), until industry-wide confidence is gained in the security of the latter. I expect a lot of interesting attacks to be found in PQ algorithms during that time, and eventually we'll settle on constructions that are secure without pre-quantum cryptography.

Note: Symmetric cryptography is largely unaffected by quantum computers. You essentially halve the security levels (nitpick: which is an exponent, so you'll effectively be taking the square root of the possible values rather than just "halving it", which would just shave off one bit).

Quantum key distribution and other entangled photon madness? I doubt we'll see widespread deployment of this.

EDIT: I see this article isn't the author's first inaccurate foray into this topic. They might want to consult a cryptographer before publishing bunk science. https://www.scientificamerican.com/article/the-quantum-inter...