Dr. Leemon Baird of Hedera said that the key size of digital signatures must be increased to be secure in the world of quantum computers.
As the world waits for the first true quantum computers to become a reality, 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 could also pose a threat to the current cryptographic algorithms many digital services rely on.
Encryption involves complex math problems that modern computers cannot solve to keep data secure. But quantum computers could become advanced enough to break through modern encryption measures. The predicted fallout from these machines is known as the “quantum apocalypse”.
One area that may be at risk is cryptocurrencies. As the name suggests, these digital currencies rely on cryptography to confirm transactions.
Research by Deloitte estimates that more than 4 million bitcoins in circulation could be vulnerable to future quantum attacks. This compares to roughly $77 billion in value, based on the current price of bitcoin.
Dr Leemon Baird is co-founder of Hedera, a public proof-of-stake network designed for businesses. Baird told SiliconRepublic.com that in a “nightmare scenario” where the crypto 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 tell if tokens have been transferred from your account,” Baird said.
“Somebody can steal everything you have, all your cryptocurrency, all your tokens, they could do anything in your name because your name is just a signature and they can forge your signature.
“And you can even do weird things like double spin, where you break the blockchain itself because you’ve broken the hash function.”
However, Baird said this scenario is highly unlikely as the industry is already “fully aware” of the risks that quantum computers could pose. He also explained that it may be relatively easy to protect parts of the blockchain against this quantum threat, even if it comes at a cost.
Digital signatures
Baird said certain upgrades needed to protect against quantum computers are relatively simple, such as hashing. Simply put, this is when an input string of data of any length is changed to an output of a fixed length.
This helps keep transactions secure as it makes it extremely difficult to guess the actual length of input data. By creating a “slightly larger hash,” Baird said, data can be protected against quantum computers.
The “big problem” is in digital signatures, which are required to prove that every transaction that takes 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 could become secure from future quantum computers. The question is the amount by which they must be increased.
Currently, Baird said a digital signature is around 64 bytes in size, with transactions ranging from 100 to 200 bytes. The Falcon algorithm changes this to 1300 bytes.
Falcon is one of four encryption algorithms designed to be able to withstand a quantum computer attack. These algorithms were selected by the US National Institute of Standards and Technology earlier this year to form a new cryptographic standard.
“That 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.”
He added that this could cause everything in the blockchain to be slower and “a bit more expensive”. However, he believes that technological advances over a short period of time will make the increased size more manageable.
“No one is going to die because we have put on 800 byte or 1300 byte signatures. We can survive it,” Baird said. “We will do it in two years when there is an actual standard. There is no particular rush, but we will do it.
“It’s a pain, it’s a kind of tax on all of humanity. But we pay the tax.”
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