In September 2019, Google announced the realization of quantum supremacy, completing 10,000 years of computation on a supercomputer in just 3 minutes and 20 seconds on a 53-bit quantum computer. Quantum computing has raised more concerns, not only in the field of encryption.
For digital cryptocurrencies, we don’t need to worry about Bitcoin being poached by quantum computers in 2020, but developers and companies should be prepared. For the average person, quantum computing, which needs more attention, may cost you money.
Over the past 12 months, the subject of quantum computing has attracted more and more attention in the field of digital encryption. Given the increased attention, it is worth while solving some of the problems of quantum supremacy for the digital crypto community, because there is a lot of wrong information circulating.
Will our Bitcoins be stolen?
Many worry that Google’s 54-bit quantum processor, Sycamore, could overtake existing systems and steal everyone’s bitcoins. If the current Bitcoin network is not changed, this is likely to become a reality within five to ten years. Therefore, users need not worry at the moment, but developers are advised to be prepared.
What is truly shocking is that the “quantum deniers” refute reality and insist that such fears should be contained. On the contrary, we must work together to solve this problem, because complex distributed systems are difficult to upgrade to the new cryptocurrency stack. If it takes a decade or more, quantum computing will develop to the expected level, and the ecosystem of digital encryption could be severely damaged.
To be sure, current encryption schemes, including those used by Bitcoin and Ethereum, have proven vulnerable to signature forgery that quantum computers can perform.
Asymmetric cryptography relies on key pairs (i.e. private keys and public keys), where the public key can be calculated from the private key pair, and vice versa. This is due to some mathematical problems, such as the resolution of the multiplier of a large prime number to a factor, or the calculation of the multiplier of the generator that generates the public key, which is used by most blockchain and cryptosystems.
If you can calculate it in another way (that is, from a public key), the entire scenario is broken. All we need is more stable qubits in these systems to make such attacks executable.
Bitcoin Price, source coinbase
Will Google poach all the remaining bitcoins?
This is another frequently asked question, but in fact, quantum computers are far less efficient at symmetric password-related computations than asymmetric password-related calculations. For example, on a mainstream computer it takes 2 to 128 operations to find the BTC private key for a given BTC public key, which can be implemented at a quantum computer at a cost of 128 x 3 operations.
For hash functions, the differences , though still large, are much smaller. In essence, we need to worry more about quantum computers spending or stealing people’s money than worrying about Google digging up the remaining bitcoins. Even so, after successfully mining the 2016 block, it set the difficulty to a “quantum class,” meaning bitcoin can only be mined by quantum computers.
The tricky problem is that the difficulty level has been reached, and miners have to wait to readjust the timestamp fields for a given block because they have gone through all possible random numbers for a given block without finding results below the difficulty target. In view of this, I dare say that this mining-related problem is theoretical rather than practical. We have noticed that even without digging based on quantum computation, time can be a factor that limits mining, not performance.
Pichai with Google Quantum Computer sSanta Barbara lab
One thing everyone should be concerned about
Should Bitcoin holders worry about quantum issues in 2020? The answer is no, but there is a caveat: cryptocurrencies (developer communities) and businesses should be concerned.
What if we had made quantum computers that were much more powerful than Google Sycamore, and we were not allowed to know about them?
We should seek and upgrade to the anti-quantum cryptographic stack as soon as possible in blockchain applications and all other systems that rely on asymmetric encryption (e.g., banks, governments, etc.). Quantum hegemony is inevitable, and that’s just when.
The writer, Johann Polecsak, is the co-founder and CTO of Centrum Circle, the CTO of QANplatform, responsible for technology development and a cryptocurrency consultant for the Centrum Circle project.