3 ms·

He sort of glosses by the need to upgrade from current cryptographic algorithms. But I wonder if in 20-30 years, we'll look back on the bad timing of having des

by abeppu 4y ago

He sort of glosses by the need to upgrade from current cryptographic algorithms. But I wonder if in 20-30 years, we'll look back on the bad timing of having designed blockchains before post-quantum cryptography was on solid footing. Even if there are few problems where quantum computers have a clear advantage, it seems at least unfortunate that a lot of people spent a lot of time and resources building up "value" explicitly protected by those problems ... and decentralizing them in a way that makes upgrades challenging. We like to imagine that quantum computers will be creating value for society by doing simulations about cutting-edge scientific problems. What if it just lets rich companies impersonate long-dead bitcoin whales?

tromp 4y ago
I consider the odds of having quantum computers able to break discrete log within 3 decades to be rather minute. The challenges involved seem way larger than for something like making nuclear fusion commercially viable. I also have a very hard time believing that 1) physical reality supports computing with a superposition of 2^{256} states each with an accurate amplitude of magnitude 2^{-128}, and 2) that we can engineer systems preserving such accuracies.
- abeppu 4y ago
  Care to shed more light on your intuitions? I get that the engineering challenges are hard (or we'd have figured it out by now). And everyone seems pretty bad at predicting how long it will take for us to build something fundamentally new. But from the physical impossibility side, what would have to be true/what would we learn if we discovered that physical reality _doesn't_ support quantum computation with a large number of qubits and sufficient accuracy? I did do a course which included some quantum computation material and the professor highlighted that it wasn't actually demonstrated whether nature would be so "extravagant" ... but I haven't heard anyone describe what the universe would need to be like to both support the quantum phenomena that we've already studied and demonstrated, but to disallow some larger/more complex arrangements of what seem to be the same principles.

by abeppu 4y ago

tromp 4y ago

I consider the odds of having quantum computers able to break discrete log within 3 decades to be rather minute. The challenges involved seem way larger than for something like making nuclear fusion commercially viable. I also have a very hard time believing that 1) physical reality supports computing with a superposition of 2^{256} states each with an accurate amplitude of magnitude 2^{-128}, and 2) that we can engineer systems preserving such accuracies.

abeppu 4y ago
Care to shed more light on your intuitions? I get that the engineering challenges are hard (or we'd have figured it out by now). And everyone seems pretty bad at predicting how long it will take for us to build something fundamentally new. But from the physical impossibility side, what would have to be true/what would we learn if we discovered that physical reality _doesn't_ support quantum computation with a large number of qubits and sufficient accuracy? I did do a course which included some quantum computation material and the professor highlighted that it wasn't actually demonstrated whether nature would be so "extravagant" ... but I haven't heard anyone describe what the universe would need to be like to both support the quantum phenomena that we've already studied and demonstrated, but to disallow some larger/more complex arrangements of what seem to be the same principles.