What does Google's quantum breakthrough mean for blockchain cryptography?

Over the years, we have been warned that the breakthrough in quantum computing is just around the corner. When this day comes, we are told that it may make existing encryption standards obsolete, threatening the security of each major blockchain. This day seems to finally come, Google has achieved "quantum hegemony", although this feat is exciting, but this does not mark the end of the encrypted online game, at least not yet.

They really did it – the absolute madman

Last Friday, the Financial Times published a report claiming that a paper published by Google researchers described a major breakthrough in the computer field. Using a quantum computer, the research team completed a calculation in three minutes, which would have cost the world's most powerful supercomputer for 10,000 years. In an industry that features continuous improvement, this sounds like a qualitative leap, worth comparing to the Big Bang. Researchers claim to have achieved quantum hegemony, which means that quantum computers outperformed the world's best classic computers in specific tests.

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Google described this achievement as "a milestone toward comprehensive quantum computing" and predicted that quantum computing power will expand at "double exponential rate", exceeding the exponential rate described by Moore's Law for decades. On the surface, this technology sounds like it is possible to destroy everything we cherish, starting with bitcoin. The reality is (usually): the prediction of bitcoin "death" by quantum computing is greatly exaggerated.

The rise of cryptography and anti-quantum blockchain

Because of the fear that quantum breakthroughs are imminent, threatening the sanctity of all known encryption algorithms, cryptographers have been working to develop quantum resistance chains to counter the "Cambrian explosion" in quantum computers.

Johann Polecsak, chief technology officer of the anti-quantum blockchain QAN, told news.Bitcoin.com: "The most popular public key algorithm theoretically has the risk of being broken by quantum computing. Most of the encrypted data that is intercepted and stored today may be in the near future. Decrypted by a quantum computer."

Polecsak boldly stated on Google's quantum computer (allegedly Sycamore):

"The concept of Google's quantum breakthrough sounds very compelling, but in fact, it's hard to measure its importance at this time. How do we determine that Google's quantum computer is more powerful than D-wave, for example, it surpassed 1000 quantum four years ago? Bit?"

All signatures and hashes in the QAN protocol that may be affected by quantum algorithms (usually Shor or Grover algorithm searches) are protected by post-quantum cryptography. It sounds like a cryptographic genre dedicated to protecting the networks in the quantum supercomputer world. There are many models of post-quantum cryptography, and QAN currently supports grid-based methods. Other variants of the six primary schools in post-quantum cryptography include hash-based and code-based cryptography.

Andrew Yang hints that the threat exists

One of the most difficult things in discussing quantum computing is to separate facts from fiction, to separate fear from manufacturing, and to separate theory from practice. In the field of computing, FUD and FOMO have been in short supply, which may explain why quantum threats have such a strong resonance in the field of cryptography. In the case of quantum breakthroughs, the “fairness” of Bitcoin and other cryptocurrencies depends on who you want to believe. For example, Andrew Yang, the presidential candidate who supports technology, explains in his quantum computing and encryption standards policy:

Quantum computers using qubits will theoretically be able to break the calculations necessary for our current encryption standard in one day. When this happens, all of our encrypted data will be attacked. This means that our business, communication channels and banks and national security systems are accessible.

As for when this will happen, Yang pointed out: “It has been estimated that this timeline is 10 years or less. In short, this is a problem that must be solved immediately… First, we need to invest and develop immediately. New encryption standards and systems, and immediately turned to these anti-quantum computing standards to protect our most sensitive data."

Andrew Yang

Bitcoin has not failed yet

Although advances in quantum computing deserve close attention, there is no evidence that the BTC and BCH private keys are in danger of being ejected quickly. To illustrate the security of the current encryption standard, Openbazaar's Chris Pacia published a blog post in 2013 that discussed the commonly used 128-bit Advanced Encryption Standard (AES), which concluded: "If every one of the 7 billion people on the planet A person has 10 computers to test a key combination of 1 billion per second, which takes 7.7*10^24 years to find a 128-bit AES key."

As for how fast quantum computers can achieve the same feat, Pacia admits that he is not an expert, but he boldly said: "Quantum computing may double the size of the key, and the key can be effectively forced to use. This may Causes AES-128 to fail, but AES-192 and AES-256 should still be safe."

Bitcoin mining uses SHA-256, while cryptography uses ECDSA (Elliptic Curve Digital Signature Algorithm) to create private and public key pairs. For example, in the case of quantum computer cracking SHA-256, an obvious solution is to switch to a more powerful encryption algorithm of the same kind, such as SHA-512.

As described in Wikipedia's post-quantum cryptography: "Although the quantum Grover algorithm does accelerate the attack on symmetric ciphers, double the key length can effectively block these attacks, so post-quantum symmetric cryptography and current symmetric cryptography There is no significant difference in learning. In other words, even if quantum computing does achieve scale, we are unlikely to need to completely redesign our cryptography. Instead, we only need to enforce a more powerful version of the algorithm.

As Sabine Hossenfelder summed up in a video on quantum hegemony in June:

I am not optimistic that quantum computers will soon have practical applications. I am worried that quantum computing will be like nuclear fusion: it will always have a future, but it will never work. However, quantum hegemony will be a super exciting event.

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