Securing cryptocurrency from quantum attack
Bitcoin and other cryptocurrencies will be vulnerable to attacks by quantum computers by 2027, says a team of researchers proposing measures to improve digital currency security.
“Many existing Bitcoin accounts and all new transactions will be at risk within 10 years, so we need to start thinking about solutions now,” says Dr Marco Tomamichel from the Centre for Quantum Software and Information (QSI) at the University of Technology Sydney (UTS). He is a co-author of the White Paper, Quantum attacks on Bitcoin and how to protect against them, describing how digital currencies could become vulnerable to attack with disastrous effect if thieves equipped with quantum computers steal funds without detection.
Trust in this rapidly growing market – today estimated at a worth of US$150 billion – could erode rapidly as a result.
“Understandably, there is a lot of nervousness in cryptocurrency communities about whether their digital assets will be able to resist future attacks by very fast quantum computers,” he said.
Cryptocurrency transactions are based on a public and private key. A bitcoin recipient must share the public key with the person sending the coins, and must use the private coin to spend the coins.
Any attacker who can learn the private key can then spend the funds without detection. While current computer technology is not powerful enough to crack these keys in enough time, a quantum computer could do it in just a couple of minutes.
Dr Tomamichel joins Associate Professor Gavin Brennen at Macquarie University, Professor Miklos Santha at the Centre for Quantum Technologies (CQT Singapore), and Associate Professor Troy Lee from Nanyang Technological University, Singapore in the new Quantum Resistant Coin (QRC) group bringing their knowledge of quantum technologies and cryptography to the security of digital currencies, in partnership with blockchain company Hyperchain.
The QRC team has also assessed counter-measures to attacks and the risk of quantum-dominated mining in so-called Proof of Work protocols, which are the basis for verifying transactions in Bitcoin and many other cryptocurrencies.
They offer a range of measures and alternatives to the current security protocols that could negate the threat, mainly with a different, quantum-safe public key signature scheme.
“There are alternatives to the signature scheme used by Bitcoin that are already secure from quantum computers. In principle, one could upgrade Bitcoin to include this to protect all new transactions,” Dr Tomamichel said.
Dr Adrian Lee, UTS Business School, said the Bitcoin losers are more likely to be smaller investors.
“Bitcoin and other cryptocurrencies are spreading but have not yet gained institutional acceptance with investment banks or mutual funds. It is still largely a ‘mum and dad’ speculative investment at the moment,” he said.
He believes that any security concern the business/finance sector has for breaches should be mitigated by cryptocurrencies upgrading their technology to prevent them happening.
“An example of cryptocurrencies adapting with the times is the fork of Bitcoin Cash to accommodate more transactions. So cryptocurrency foundations can update the software to adopt higher security measures to keep up with the latest technology. A cryptocurrency investor should not fear for security breaches in the long term given it is a known risk. There is an inherent risk of course that the security does not catch up with the hacking but the probability is pretty small,” he said.
QRC has been appointed as a technical advisor to Hyperchain, which provides technical services to Hcash (CoinMarketCap.com Hshare with a market capitalisation of over US$300 million) and will work with Hcash, Hshare and Hyperchain to ensure their cryptocurrency can resist quantum attacks.
“Our service is providing advice and algorithmic protocols to digital currencies and blockchains like Hcash which want to certify their product will be quantum safe. HCash has put a strong emphasis on quantum security from the outset so this collaboration will benefit both teams, and customer confidence,” he says.
“It is a very exciting time to be working in quantum information now that simple quantum machines, like the Google and IBM devices, are a reality.”