MIT's Ethan Heilman: 80% of Bitcoin is Quantum Vulnerable - How to Stop the Q-Day Threat

**Shinobi** (0:00)
When exactly is the quantum computer that's going to kill Bitcoin going to come online?

**Ethan Heilman** (0:05)
So, the actual answer is that no one knows. The timelines have been getting shorter and shorter, and we've been seeing more and more progress, not just in building quantum computers, but also the resources to pull off the attack. I have this very optimistic belief that if we were told with 100% certainty, quantum computer is going to be out in two months. I think Bitcoin could get it done, but if it happens and then it gets announced, it's much more frightening to me.

**Shinobi** (0:40)
Hello, everybody, I'm Shinobi at Bitcoin Magazine, joined today by Ethan Heilman, a research fellow at the DCI Lab at MIT. And we are here to scare you about quantum computers.
So, I guess this is probably the question everyone wants me to ask first. When exactly is the quantum computer that's going to kill Bitcoin going to come online?

**Ethan Heilman** (1:07)
So, the actual answer is that no one knows. Everyone has super strong opinions. But I think is one of those things that I feel like the more certain someone is of the number, the less certain I am of their opinion on the number. Because we could get really, really close and then hit something that would make it that stretches the timeline out, or it could look like the timeline is really far out, and then we get like one breakthrough and we get there.
So, looking at the timelines of errors people have proposed, and looking at sort of like expert opinion, the timelines have been getting shorter and shorter, and we've been seeing like more and more progress, not just in building quantum computers, but also the resources to pull off the attack, like the algorithms have been getting better and better, so they're kind of triangulating.

**Shinobi** (2:01)
Yeah, that I think is like, at least personally from my perspective, where I see the meaningful progress, is like the algorithmic optimizations.

**Ethan Heilman** (2:12)
Yeah, and that's the one that is more, that is the most frightening to me, because you have like the least warning that someone comes up with a clever idea, like hardware is wonderful in the sense that it's like, oh, it gets a little bit better, a little bit better, you can kind of like plot the curve of that, but algorithmic improvement is like, oh, that thing we thought was hard isn't hard anymore, is what frightens me the most.

**Shinobi** (2:40)
Yeah, I think a lot of people have been kind of swept up in the mania around the newest Google paper, but that is a perfect example of that. Like that was a purely algorithmic optimization requiring a whole new physical architecture design for how to build a quantum computer.
And like that is kind of being paraded around as like, oh, like the clock is ticking, it's time to like fix things now, like this is serious. When in like reality, from my perspective, all that is, is like we're starting again with a new design. And each previous design, you know, made their breakthroughs, their progress, but it's like nothing has quite just taken off and started scaling or having like massive improvements over generational iterations.

**Ethan Heilman** (3:36)
So I think there's actually like two papers that came out around the same time and at the Google paper references. So one of the papers is this neutral atoms quantum computer, which is like a new architecture.
And it's both scary because it can do a bunch of things that the previous architectures couldn't. But at the same time, there's a little bit more like skepticism of it because it's like less well known. And then there's the superconducting like silicon qubits work. And the Google paper looks at both of them. But one of their innovations is to the sort of traditional quantum computer with like a superconducting qubits.
And what's really sort of scary is that if you plotted it on the number of logical qubits you'd need, they made it 20 times easier.
And the neutral atoms one also, they show that it's significantly easier. And then there was the neutral atoms paper that they like reference. But the most worrying thing for me is that I think we're getting to the point that the people working on quantum computers like Google or like the people working on neutral atoms quantum computers, they believe that they're close enough that maybe they'll publish like one more paper or maybe they won't. But they're probably going to start going to skunk's mood. And so we're going to stop getting warnings.
And I think the most helpful thing for all of this is having those warnings. Because it's like, oh, we're getting closer, we're getting closer and it kind of like lights a fire under people's asses. And I have this very optimistic belief that like, if we were told with 100% certainty, quantum computer is going to be out in like two months, I think Bitcoin could get it done. Like it would be like a massive project, and there would be a bunch of addresses that would like get left behind. But like, if you know when it's going to happen, people care enough that they'll like figure out a way to make it work. But if it happens and then it gets announced, it's like much more frightening to me. So I'm starting to worry, especially with the fact that some of the circuits were approved that they worked, but they weren't released, is the concern of proprietary information.