In cryptography there is a 20-30 year lifecycle for an algorithm before it gets exceeded by new technologies and developments in mathematics. Both the signing and hashing algorithms can be upgraded in Bitcoin if there is a need to do that. Quantum cryptography represents a threat only if unevenly distributed in commercial sectors.
If it is available to only one actor, and not all actors, they are unlikely to use it against Bitcoin; instead they're going to keep it secret and use it when they're threatened by ex. cryptographically secure nuclear weapons. Intelligence agencies who have that kind of significant computing advantage don't use it until there is a dire emergency, because once you use it everyone will know you have it.
After that all the algorithms get changed, so you better make it good. If it is widely available, all the miners update to quantum computers and we're going to be looking at several orders of magnitude in improvement, because running one is neither free nor easy. We don't know what the economics will be yet, but we will solve problems when it's necessary.
Corporations and governments are not going to be happy with Bitcoin. Kings were not happy and yet the revolution happened anyway. Bitcoin is a global and technological revolution. They have adapted to new technologies for hundreds of years. The fact that they won't be happy doesn't concern me, because Bitcoin is a system that doesn't require their permission, approval, or cooperation.
They can pretend it's going away but it isn't. We can talk all day about whether the government should or shouldn't regulate Bitcoin, but the real question is whether they can. They can regulate at the edge, the behaviour of users, but they can't regulate Bitcoin itself. Bitcoin is exciting because it introduces a new choice; it's not saying you can't do the old way (hierarchical central banking, border-restricted jurisdictions for currencies ), it's saying we can also do this.
Transcript
[AUDIENCE] I have two questions that are- [ANDREAS] Two questions? Okay, fine. [AUDIENCE] Both of them are about risks against Bitcoin. The first one is technological.
Recently, the National Institute of Standards and Technology (NIST)... said it is time to start promoting migration to post-quantum cryptography, because... [quantum computing] will weaken the asymmetric cryptography of SHA-256. We are talking about an attack of 51%, but in that case it will take ten or twenty years [to create] a 99% attack.
One bad actor with a quantum computer will be spending much less energy than anyone else, and will acquire 99% of the hashing power. [ANDREAS] If it is 99%, it is not an attack. You realize that? [AUDIENCE] Yeah, it is a monopoly.
[ANDREAS] Well, not necessarily. [AUDIENCE] Very quickly- [ANDREAS] That is the first question? [AUDIENCE] Yes. So do we change the algorithm?
Move to proof-of-stake? Things like that. The second question is about the corporations... and governments, who will not be happy with Bitcoin.
[ANDREAS] Oh no, [they won't be happy?] [Laughter] [AUDIENCE] Bitcoin's community will need to respond. Any ideas about this? [ANDREAS] Okay, great. First question, quantum cryptography and more specifically quantum cryptanalysis.
At some point, quantum computing will exceed the [strength] of current cryptographic algorithms. Listen, that is part of [developing] cryptography. You have twenty to thirty years of usable life cycle... an algorithm before it is [broken] due to new developments in mathematics and technology, etc.
Bitcoin is such that it can be upgraded; both the signing algorithm and the hashing algorithm can be switched... for other algorithms if we think there is a need to do that. Quantum [computing] represents a threat only if it is unevenly distributed in commercial sectors. But if quantum [computing] and cryptanalysis is available only to one actor, mostly likely they are a state actor and they will not use it on Bitcoin.
[Instead], they will keep it secret and use it at a time when they are threatened, such as... by a cryptographically secured nuclear weapon or whatever, some crazy [situation] like that. Certainly, what we've seen with intelligence agencies that have computing advantages, they don't use it until there is a dire emergency, and Bitcoin is not a dire emergency. Once you use it and everybody knows you have it, then all the algorithms will be changed.
You have one shot, so you better make it good. If quantum computing is available broadly, then miners upgrade to quantum computers and use quantum SHA. Crois-SHA-ntum. [Laughter] Something like that.
I don't know. We would change the algorithms. If there is enough availability of quantum computing that 99% of mining capacity switched over, the chance... the chance that it will be controlled by one person is pretty slim.
[An attack would just prompt] everybody to run 'quantum SHA,' and it will be a transition like when we went from... FPGA to ASIC. We will see a different order of magnitude or several orders of magnitude improvement. Keep in mind that running a quantum computer is neither free nor easy, right?
It will be expensive in terms of energy and cooling costs. The electricity that you are not spending [on hashing]... will be spent on keeping the [machine] at 200 degrees below zero. All of these things add up.
We don't know what the economics will be. I try not to solve problems until problems come up. Bitcoin is very much a system where we solve problems when it is necessary to solve them. We will see.
As for the second [question about] corporations and governments not being happy, I'm sure that they won't be happy. I believe this is the [point] where people decided that the King wouldn't be too happy with their choices. Kings were not happy anywhere, and yet the revolution happened anyway. Bitcoin is a technological revolution.
It is a global system. Corporations and governments must adapt to new technology. They have been adapting to new technologies for hundreds, sometimes thousands, of years. They will adapt to Bitcoin, which is neither the worst thing nor the most insurmountable thing to happen.
There could be far worse cryptocurrencies than Bitcoin from the perspective of governments. But the fact that governments will not be happy really doesn't concern me much. Bitcoin is a system that does not require their permission, approval, cooperation, endorsement, or assistance. It is a system that simply exists now.
[They] can deny that it exists, but it still exists. [They] can pretend it will go away, but it isn't. We can talk all day about whether the government should or shouldn't regulate Bitcoin. The difficult question is whether governments can regulate Bitcoin.
The answer is simple: they can't. They can't regulate Bitcoin itself. They can regulate the edges, the behaviour of some users within their borders, under certain circumstances, but the truth is that they can't really regulate Bitcoin itself. Governments and corporations will need to adapt.
I think that is a feature of Bitcoin, not a bug. I think that is one of the reasons why Bitcoin is so exciting to a lot of people. It introduces a new choice. It is not saying you can't [do money] the old way, in hierarchical organizations, restricted within one border and jurisdiction, and banking with a central bank.
You can still do all of those things. But we will also do this and see which one is better. That is really the bottom line.