[kmeisthax]

They can fundamentally break most asymmetric encryption, which is a good thing iff you want to do things that require forging signatures. Things like jailbreaks Apple can't patch, decryption tools that can break all E2E encryption, being able to easily steal your neighbor's Facebook login at the coffee shop...

Come to think of it, maybe we shouldn't invent quantum computers[0].

[0] Yes, even with the upside of permanently jailbreakable iPhones.

[dvh]

No you can't. Largest factored number using shor's algorithm is 21. No other algorithm scales to crypto levels.

[rocqua]

You can't use shor's algorithm with current quantum computers.

But if we were to get bigger and better quantum computers, we should use shor's algorithm. And that would, in fact, break the crypto behind HTTPS, SSH, smard-cards, and effectively all other forms of asymmetric crypto that are in use.

There is a question how likely bigger and better quantum computers are. A decent case can be made that it is unlikely they will grow fast. But it is going to far to say that shor's algorithm is useless because current quantum computers aren't good enough. You can't dismiss the possibility of quantum computer growth out of hand.

[seccode]

I think I heard that 77 was factored as well