Talk about how quantum computing, as I understand it, affects cryptocurrencies?

A few days ago, on November 30th, a major forum on "quantum computing" and "block chain" was held at South China University of Technology in Guangzhou.

The full name of this forum is "Quantum Information and Blockchain Technology". It was initiated by Professor Zhu Jiaming, director of the Academic and Technical Committee of the Digital Asset Research Institute, and co-sponsored by the Digital Asset Research Institute and the School of Automation Science and Engineering of South China University of Technology.

As a guest, I was also invited to participate in this conference. There were some quite in-depth discussions that could explain and clarify the current fear of quantum attacks in the blockchain field. This blockchain has a deeper understanding of this field and has more confidence.

When it comes to quantum computing, the biggest news this year is that Google announced the invention of a 53-qubit quantum computer, winning the so-called "quantum supremacy."

When the news came out, it was discussed in the press as a great technological advance, causing a stir, but nothing more. In the entire blockchain industry, it has caused panic, why? Because people who did not understand the details and quantum computing for a while began to spread rumors that digital currency was about to be broken by quantum attacks.

Mr. Ren Zhengfei of Huawei even made a statement that "many people say how great the blockchain is, but it is worthless in front of quantum computing".

Is this really the case?

I have made a special explanation for this in previous articles, but after participating in this forum and gaining a deeper understanding of quantum computing, looking back at this point of view now, I think it should be more popular and easy. Knowing the way allows digital currency holders to feel at ease, feel at ease, and have confidence in the digital currency in their hands.

First of all, we need to understand that any technology has both advantages and disadvantages, and no technology is omnipotent. The same is true for quantum computing technology.

The advantage of quantum computing is that it takes much less time to calculate certain problems than traditional computers. How much less? For example, a problem that would take a conventional computer 10,000 years to solve can be solved by a quantum computer in just one second. But note that this is only for "certain" problems.

In other words, for other problems, quantum computers have no advantage over traditional computers, which is the shortcoming of quantum computing.

This is the key to understanding quantum computing

So for which problems do quantum computers have an advantage over classical computers? It is precisely the encryption algorithm used by existing digital currencies.

This is the root of all fear.

In this regard, we assume that the existing digital currency encryption technology will not be updated or modified, so what kind of quantum computer can be broken?

According to a more reasonable guess, a quantum computer with about 4,000 qubits is required. Such a quantum computer can break the private key of Bitcoin within 30 minutes, that is, the private key can be deduced through the public key.

And when might such a quantum computer come out? The estimated time is 2027, which is 8 years later.

So if such a quantum computer really comes out 8 years later, will Bitcoin be helpless from time to time? Absolutely not.

In my sharing just now, I mentioned that the method of quantum computing to break Bitcoin is to deduce the private key through the public key. So if the public key of a Bitcoin account is not published, the quantum computer cannot find the target and cannot calculate the private key.

From here we have found the first method for Bitcoin to fight against quantum computers: a public key is only used once, and after the public key is used up, if there is no Bitcoin in the account corresponding to that public key, then even if the quantum computer calculates the private key It doesn't make sense anymore.

In fact, many bitcoin wallets use this method now. A wallet can generate as many public keys and addresses as you want, and a public key and address are only used once. So with this type of wallet, even if quantum computers come, your bitcoins are still safe!

The above is the most intuitive way to fight against quantum computing. In fact, there is a more thorough method, which is to completely avoid the advantages of quantum computing and look for its weaknesses.

As I just said, quantum computers only have advantages over traditional computers for certain problems, but not in other fields. Therefore, digital currency can completely replace existing algorithms with other mathematical algorithms that do not have advantages in quantum computing. In this way, even if quantum computers appear, there is nothing terrible.