Since the advent of bitcoin, the threat of quantum computing has motivated researchers, technologists and, now, governments, to build software able to resist attack by even the most powerful quantum computers. A headline was all over the place this week that Google has made a recent quantum computing breakthrough, which the tech media has called quantum supremacy. It is being reported that Google, using a quantum computer, managed to perform a calculation in just over three minutes that would take the world’s most powerful supercomputer 10,000 years. However, the term quantum supremacy refers to the moment when a quantum computer manages to outperform the world’s best classical computer in a determined test. This is just the first step, but it is a rather large step that means the spotlight is once again on blockchain to try and resist this kind of technology which can unravel its cryptographic algorithms in minutes. Details are a little scarce on what Google has achieved, and how they have done it, but previous proposals essentially involve the quantum computer racing a classical computer simulating a random quantum circuit.
According to Gizmodo, Google has been testing a 72-qubit device called Bristlecone with which it hoped to achieve quantum supremacy and the initial report from the Financial Times says that the supremacy experiment was instead performed with a 53-qubit processor codenamed Sycamore. Qubits, or quantum bits, are the basic unit of quantum information which uses the properties of a quantum system, such as the polarization of a photon or the spin of an electron (unlike traditional computers store and process binary data as a series of ‘1’s and ‘0’s).
The Quantum Ecosystem is ripening and it can be seen from the public reports published by market intelligence firms. According to CB Insights, which found the number of investments in private quantum computing startups has increased over 200% in the past six years.
Bitcoin, cryptography, and encryption rely on complex mathematical problems and the fundamentals provide the basis of trust in digital communications. It is not as if quantum computing will, like a light switch, be available and all blockchains will suddenly be vulnerable — but it is still important to be prepared. There are actually a few different ways a quantum computer can snap a blockchain.
- For one, blockchain transactions are secured with digital signatures based on elliptic curve cryptography (ECC). ECC coincidently is also used on the internet to encrypt user data and website traffic. However, ECC is not “quantum-safe,” meaning that a powerful quantum computer could theoretically decrypt user private keys and forge transaction signatures on their behalf. If someone has your public key, they can also calculate your private key, which is unthinkable using even today’s most powerful classical computers. But in the days of quantum computers, the public-private key pair will be the weak link. This is by far the most pertinent security issue for blockchains when it comes to co-existing in a world with quantum computers — especially given that researchers and mathematicians are already aware of a possible algorithm that could be used by a sufficiently powerful quantum computer to break elliptic curve digital signatures.
- Another thing to consider is that a quantum computer can achieve impressive speeds because qubits work at the subatomic level. Existing physical and hardware restraints make scalability of qubits highly complex and uncertain right now. Even when quantum computers become scalable, the natural progression of software is expected to match the progress made by hardware and encryption methods which should evolve to be safely implemented on blockchains like Bitcoin.
However, it would be a little early to start abandoning all hope with Bitcoin, blockchain, and the emerging technology as it is a bit more complicated than that.
In the event of quantum computers cracking SHA-256, for example, an obvious solution would be to switch to a stronger encryption algorithm of the same family, such as SHA-512. Furthermore, there are methods to encrypt information even after quantum computers. Researchers have developed methods of cryptography that use principles of quantum mechanics to safely secure information. The only problem lies in implementing such cryptography into preexisting systems.
- The National Research Council (NRC) of Canada partnered with the University of Waterloo to launch a two-year research initiative for quantum-safe blockchain technology.
- The research, led by University of Waterloo professors Srinivasan Keshav and Michele Mosca, is receiving a total of $180,000 over this two-year period to expand the team with other “highly qualified personnel,” said Nic Defalco, communications advisor to the NRC.
- The US National Security Agency (NSA) may be developing a quantum-resistant cryptocurrency. It was reported by Bloomberg Technology journalist William Turton, who attended the annual Billington CyberSecurity Summit in Washington. The information provided by Turton does not abound in detail. “Anne Neuberger, Director of NSA’s new Cybersecurity Directorate says that the agency will propose hardware and software standards again. Also notes agency is working to build quantum-resistant crypto” Turton writes on Twitter. The reasons for the NSA’s potential interest in developing such a cryptocurrency are unclear, but experts agree that quantum computing is a threat to cryptography mechanisms, albeit so far distant.
The reality is, as so often the case, more nuanced — predictions of Bitcoin’s death in a post-quantum era have been greatly exaggerated. It may not be the kill switch that everyone imagines because of media hype, but it certainly something that should be on the radar for anyone involved in the ecosystem.
Instead of making it a rat race, both the technologies should be focussed on being turtles where consistent and all-inclusive efforts are put in quantum and blockchain technology to assist or make the dynamics of infrastructure collaborative and not conflictive. If Bitcoin’s blockchain possesses such a near threat from quantum computers, other altcoin blockchains are worse off. However, as mentioned earlier, it is too soon to juxtapose them and measure the danger blockchains will encounter as we believe next 3–4 years are going to be extremely crucial to track the progress and competence of both the technologies.