Quantum computers are nowhere near usable for breaking classical cryptography at the moment, though opinions on how soon it will come vary. As others have said, we have quantum resistant algorithms ready to go, so future encryption is fine.
The greater concern is that a lot of traffic and data encrypted using classical algorithms has been logged or stored in various mediums. An old encrypted drive, or communications stored by nation state actors (the NSA and such). These will be broken, and a lot of past secrets might come out from hiding.
An old encrypted drive
All of these use ciphers that are only affected by Grover's algorithm. This basically halves the exponent on your key space (so instead of 2^128 keys you only have 2^64 keys), however this doesn't necessarily mean that the algorithm is faster than a good parallel brute force on classical computers.
The more problematic algorithms are the ones affected by Shor's algorithm, which are all algorithms in broad use today that involve some sort of agreeing on a shared secret.
I'm not well versed on the speed of Grover's over classical brute force. According to NIST this is correct! Thanks for the addition.
Meh... we used to use much weaker encryption algorithms, and kept upgrading those algorithms. This will just be another phase of making stronger encryption algorithms. AES-256 is already quantum resistant, we just need to work on a quantum resistant asymmetric system. Pretty sure we can get it done before a quantum computer with enough qbits is invented.
This video by Veritasium was pretty insightful on the topic.
But I guess we'll have to see about "store now, decrypt later"...
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New assymetric algos exist and the new standard is worked on right now IIRC (it might have been done already).
At 17:42 in the vid he talks about now algorithms, specifically one with vectors. His explanation is pretty good and comprehensable for not mathematically gifted people
Not happening soon and when it does, we'll have better algorithms that can't be cracked by quantum computers.
There are already quite a few approaches to quantum safe encryption. We'll just have to switch to different algorithms. It's really nothing to worry about.
I'll believe it when I see it. There's a long, long way to go between current quantum tech and something that can crack modern 4096-bit RSA.
And honestly, it'll probably come so slowly that we'll have all switched to better algorithms by the time RSA cracking becomes feasible. (Yeah, I know about store now decrypt later, but that won't really affect the average person if it takes decades to come to fruition.)
It reminds me I could store my public key in the avatar. We may have to make things more difficult with steg.
Wouldn't it still take them a very long time to break modern encryption?
And what about if someone made new encryption with quantum computers?
I assume it's inevitable and there are people working on a solution. That aside, I'm pretty excited to see what quantum computing will be capable of in our lifetime.
It's been known to be an issue for a very long time now. It is what it is. Nothing is going to change the fact that my data will be decrypted.
