“Quantum-Safe” Crypto Hacked by 10-Year-Old PC

Post by jabbany » Sun, Aug 21, 2022, 6:01 PM UTC

DarkmSparks wrote: post #178

jabbany wrote: post #176

Earlier quoted context omitted.

Wait, isn't the point of post-quantum crypto to be as good as existing crypto but also be secure against known quantum attacks like Shor's algorithm and factoring. I don't think the goal is to trade off anything for defenses against quantum attacks. If anything these stories should be more confidence inducing. They show that the rollout is conservative and that the system works. PQC algorithm has a flaw and it is fou…

The problem they are trying to solve is how to do encryption in a world when finding solutions to any and all math problems is quick and easy. And this article only reinforces the idea that the solutions they are coming up with are just obfuscation that is at best no harder than existing problems.

Post by jabbany » Mon, Aug 22, 2022, 2:19 PM UTC

DarkmSparks wrote: post #182

jabbany wrote: post #181

Earlier quoted context omitted.

Even theoretically, quantum doesn't make _all_ math problems easy... Can't they just avoid the things (like factoring) that are potentially vulnerable and just use other math?

The way quantum computers are purported to work, is they search a problem space simultaneously for all solutions, then spit out the correct solution. It could be a factorisation problem, or any other. for cryptography find x and y when f(x,y)=z given z That is what "post quantum computing" means, aiui. It starts with x and y in all possible values of x and y, then spits out only the values that give z. All encryption…

Post by jongjong » Wed, Aug 24, 2022, 12:32 AM UTC

tptacek wrote: post #174

jongjong wrote: post #165

That's why I like simple hash-based cryptographic algorithms such as Lamport OTP for digital signatures. Hash-based algorithms are broadly believed to be quantum-resistant and this makes sense intuitively because hashing destroys information. The statefulness of Lamport OTP adds some implementation and usability hurdles but IMO, the simplicity and intuitiveness of the algorithm makes it worthwhile. Source: I worked o…

We're discussing key exchange mechanisms, not signatures. The distinction is important: KEMs are what we need now if QC is a real threat, because they're what enable us to protect traffic from retroactive decryption.

Post by luc4 » Wed, Aug 24, 2022, 7:07 PM UTC

spywaregorilla wrote: post #172

luc4 wrote: post #135

Earlier quoted context omitted.

A larger number of qubits allows us to do effective quantum error correction. The idea is to group multiple physical qubits into one logical qubit, think of it as redundancy.

So what's the number of logical qubits we have achieved working practically then? Is this scalable, or is it just going to exponentially require physical qubits for each additional logical qubit? Genuine question. I've no idea.