Andreas Antonopoulos is a well-known visionary and speaker within the Bitcoin community. Lately, there’s been a lot of conversations and media headlines discussing the development of quantum computers breaking elliptic curve cryptography. Antonopoulos believes Bitcoin will be okay if the system upgrades, as research in quantum computing develops further. The technical expert also details that Satoshi’s genius back in the day had preconceived plans on how to handle the issue of quantum computing.
Breaking Bitcoin’s Elliptic Curve Would Reveal The Most Important Secret
An attendee listening to a keynote speech given by Andreas Antonopoulos asks: “Is it possible, for example, that the NSA boasts a quantum computer that will be able to break Bitcoin’s cryptography?”
“Yes, it is certain that the NSA has already built quantum computers, because Google has one in their data center, and if they have one the NSA has one that is ten times better, that costs as much as a moon mission and that can break encryption systems at a much better rate and with more efficiency,” explains Antonopoulos. “Now here’s the interesting question — Do they use that to break Bitcoin?”
“The simple answer is ‘no’. We know from history that if you have such a thing, this is the most important and well-guarded secret. Any time you use it you have to come up with a parallel construction story that tells the world how you managed to break that encryption without using such a thing, because such a thing doesn’t exist. When the British captured the Enigma they would let ships sink because they didn’t have a good enough story of how they knew the U-boat was going to be there. They let cities be bombed because they didn’t have a good enough story of how they knew they were going to be bombed and so if they couldn’t create a good enough story they could not risk revealing the most important secret they have.”
The last thing they are going to use that on is Bitcoin. Cause the moment you use it on Bitcoin you announce to the world we have quantum cryptography that can break elliptic curve — Guess what happens? Your nuclear rivals upgrade their cryptography very easily and try to implement quantum resistant cryptographic algorithms — of which there is a lot of research and a lot of suitable candidates. And you just blew all of your research and advancement in that technology on fighting a shitty little currency that some weirdos use in Prague.
Satoshi’s Two Design Choices that are Absolutely Genius
During the discussions on the topic of quantum computers breaking Bitcoin’s cryptography, Antonopoulos says there are two fundamental cryptographic systems that keep Bitcoin safe. The way Satoshi designed these elements was not an accident, explains Antonopoulos.
“No, the NSA is not going to hack us with their quantum computer,” Antonopoulos detailed to the crowd. “The interesting thing is what happens when that technology becomes commercially viable and more broadly available. That’s where you see two of Satoshi’s initial design choices that in retrospect are absolutely genius. First of all, Bitcoin uses two fundamental cryptographic systems in order to achieve its security. One is elliptic curve multiplication on a prime field which is a one-way function. That depends on prime factorization mathematics which is vulnerable to quantum technology. The other is hash algorithms, and hash algorithms are not actually factorizable with quantum technology. We don’t have very good algorithms for breaking hashes with quantum computing.”
So what does Satoshi do, he doesn’t put the elliptic curve public keys in the transactions until after they have been spent. What you use as a Bitcoin address is a double-hashed version of your public key — Which means that the public key is never seen by anyone until you claim it by spending the transaction. — Therefore if you use the fundamental best practice of Bitcoin, which is only using an address once, use a different address for every transaction, spend it completely every time you use it to redirect the change to a new address. The first time your public key is advertised on the network is the moment that it no longer contains any money — Go ahead and crack it you got an empty address.
The Second Layer of Abstraction Will Help Until the Need to Upgrade
Antonopoulos believes Satoshi’s choice to add these two layers of protection was quite genius. In the future, the community will have to prepare for quantum level computers that could crack elliptic curve, and when that happens, the protocol will have to upgrade.
“All of this 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. All you have if they haven’t been spent is the double hash of an address. This little genius design element is not an accident. What it does is, it creates a second abstraction layer of the underlying cryptographic algorithm used in elliptic curve digital signatures allowing you to do future upgrades. Which means that the past is secure because it is hidden behind the second veil of a different algorithm and the future can be changed because you can present an address that is not the hash of an elliptic curve, or its the hash of a different elliptic curve, or its the hash of a bigger elliptic curve, or its the hash of a signing algorithm that is quantum resistant that has nothing to do with elliptic curve. So, you can do a forward modification to secure the future, and you’ve got backward protection because you have hid the past.”
He adds: “A brilliant little design element that most people have missed. So quantum computers — we upgrade.”
Images courtesy of Shutterstock, Antonopoulos.com, and Bitcoin.com