Dr Leemon Baird of Hedera told SiliconRepublic.com that digital signatures may rise from 64 bytes to 1,300 bytes to be safe from quantum computers.
As the world waits for the first true quantum computers to drop, various industries are taking steps to prepare for their arrival.
These powerful machines are expected to surpass modern computers in almost every way, performing calculations that would otherwise be impossible.
This could lead to enormous benefits for humanity, but it also poses a threat to the cryptographic algorithms many digital services rely on. The predicted fallout from these machines is known as the quantum apocalypse.
One area that could be at risk from quantum computers is the cryptocurrency industry. As the name suggests, these digital currencies rely on cryptography to verify their transactions.
Research from Deloitte estimates that around 4m bitcoins in circulation could be vulnerable to future quantum attacks. This compares to roughly $77bn in value, based on the current price of bitcoin.
Dr Leemon Baird is the co-founder of Hedera, a public proof-of-stake network designed for enterprises. Baird told SiliconRepublic.com that in a “nightmare scenario” where the industry takes no steps to prepare, the results could be very damaging.
“What it would mean is that you could break the signature system that allows you to say whether or not tokens are transferred out of your account,” Baird said.
“Someone could steal everything you have, all of your cryptocurrency, all of your tokens, they could do anything in your name because your name is just a signature and they could forge your signature.
“And you could even do weird things like double spins, where you break the blockchain itself because you’ve broken the hash function.”
However, Baird said that this scenario is very unlikely as the industry is already “fully aware” of the risk that quantum computers could pose. He also explained that it can be relatively easy to protect parts of the blockchain from this quantum threat, though it comes at a cost.
Baird said certain upgrades that are needed to protect against quantum computers are relatively straightforward, such as hashing. In simple terms, this is when an input string of any length is changed to an output of a fixed length.
This helps to keep transactions secure as it makes it extremely difficult to guess the actual length of the input. By creating a “slightly bigger hash”, Baird said this section can be protected from quantum computers.
The “big issue” is in digital signatures, which are required to prove each transaction taking place on the blockchain is valid.
“It’s all anonymous, how else would you prove it? You have to prove that you have this key by signing something,” Baird said. “Digital Signatures are the part where this is painful, very painful.”
Baird said that with larger key sizes, digital signatures can become safe from future quantum computers. The issue is the amount they have to be increased by.
Currently, Baird said a digital signature is around 64 bytes in size, with transactions ranging from 100 to 200 bytes. The Falcon algorithm, which Baird said is the smallest, changes this to 1,300 bytes.
Falcon is one of four encryption algorithms that are believed to be capable of withstanding a quantum computers assault. These algorithms were selected by the US National Institute of Standards and Technology earlier this year to form a new cryptographic standard.
“It means you have to send more bytes, you have to store more bytes, you have to process more bytes,” Baird said. “Everything is a pain.”
Baird said this could cause everything in the blockchain to become slower and “a bit more expensive”. However, he believes that over a short period of time, technology advances will make the increased size more manageable.
“No one’s going to die because we have put on 800 bytes or 1300 bytes signatures, we can survive it,” Baird said. “We’ll do it two years from now when there’s an actual standard. There’s no particular rush, but we will do it.
“It’s a pain, it’s sort of a tax on all humanity. But we’ll pay the tax.”
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