Could the NSA build a quantum computer that could break bitcoin? Bitcoin visionary Andreas Antonopoulos addressed this question in an audiotaped presentation posted on SoundCloud. “It is certain that the NSA has already built quantum computers because Google has one at their data center, and…
Could the NSA build a quantum computer that could break bitcoin? Bitcoin visionary Andreas Antonopoulos addressed this question in an audiotaped presentation posted on SoundCloud.
“It is certain that the NSA has already built quantum computers because Google has one at their data center, and if they have one, the NSA has one that’s ten times better, that costs as much as a moon mission, and can break encryption systems at a much better rate and with much more efficiency,” he said.
The interesting question is: will they use it to break bitcoin? The answer to this question is “no,” Antonopoulos said. The most important well-guarded secret among encryption scientists is that if you use a technology to break encryption, you will have to explain to the world how you broke it.
In World War II, when the British captured Enigma (cipher machines developed by the Germans to protect military intelligence), the government allowed cities to be bombed since they didn’t have a good enough story for how they knew they would be bombed.
“The last thing they’re going to use that on is bitcoin, because the moment you use it on bitcoin and you announce to the world we have quantum cryptography that can build elliptic curves, guess what happens?” Your rivals try to implement quantum resistance. “You just blew all of your advancements in that technology,” he stated.
“No, the NSA is not going to hack us with their quantum computer,” Antonopoulos said. But what happens when the technology becomes commercially viable and more broadly available?
Nothing to fear, according to Antonopoulos, thanks to bitcoin’s design. “That’s where you see two Satoshi’s initial design choices in retrospect are absolutely genius,” he said.
Bitcoin uses two fundamental cryptographic systems to achieve its security.
One is elliptic curve multiplication on a prime field which is a one-way function. This depends on prime function factorization mathematics that is vulnerable to quantum technology.
“The other is hash algorithms, and hash algorithms are not actually factorizable with quantum technology,” he said. “We don’t have very good algorithms for breaking hashes with Quantum computing.”
Satoshi didn’t put the elliptic curve public keys in the transactions until after they’ve been spent. A bitcoin address is a double-hashed version of a public key, meaning the public key is never seen by anyone until the user claims it by spending the transaction.
Therefore, if one follows the fundamental best practice in spending bitcoin – which is to only use an address once, use a different address for every transaction and spend it completely every time– the first time the public key is advertised on the network is the moment it no longer contains any money.
“Go ahead and crack it; you’ve got an empty address,” he said. “And that means you can’t go back and look at keys that were addresses three years ago and simply crack them because you don’t have the public keys.”
“This little genius of a design element is not an accident,” he said. It allows the user to do future upgrades.
He called it a brilliant design element that most people have missed.
Every cryptographic algorithm ever invented has a shelf life between 20 and 30 years before becoming vulnerable to broadly available commercial technology that can crack it, he said.
“It’s a continuous arms race,” he said. The good news is we can upgrade.
Featured image from Shutterstock.
Last modified: January 26, 2020 12:04 AM UTC