Google claims to achieve quantum hegemony, where should digital currency go?

On September 20 this year, Google announced that "quantum supremacy" had been realized. They proved the superiority of quantum computers over traditional architecture computers in experiments for the first time: in the world's first supercomputing Summit, which required calculations for 10,000 years, Google's The quantum computer took just 3 minutes and 20 seconds. This landmark paper not only caused a sensation in the quantum physics circle, but also sparked heated discussions among outsiders. Everyone probably knows by now that quantum computers are awesome. So what is the difference between it and the operation mode of traditional computers?

In a traditional computer, a transistor is the most basic unit that allows a computer to process data. Functionally, it is like a switch, which can block or allow current to pass through. High and low electrical signals make up data, that is, bits—for a bit, there are Both 0 and 1. Engineers express different words, symbols or logic with different sequences of 0 and 1 by establishing an instruction set. The more bits there are, the larger the data that can be represented.

Therefore, in the field of traditional computers, the more transistors there are, the more information can be processed per unit time and the higher the computing power. Today, a transistor in a computer can already be a few nanometers in size. But at present, human beings have encountered a real physical barrier: transistors can no longer be made smaller, and Moore's Law (the amount that can be accommodated on an integrated circuittransistornumber, doubling about every two years) also failed.

The birth of quantum computers is expected to break the physical barrier of transistors. In a quantum computer, qubits can be set to either 0 or 1. Moreover, in the quantum world, qubits can be in multiple states at the same time, and it can be any linear combination of several different quantum states. This state is what we often hear: quantum superposition state, quantum superposition state Features bring great possibilities for change.

When a traditional bit represents 16 possible combinations, you can only choose one of them, but in a qubit in a superposition state, you can think of it as being in all 16 states at the same time. So you only need 4 qubits to represent 2 to the 4th power of traditional bits of data—every bit more, the advantage of a quantum computer doubles exponentially.

This is why Google's quantum computer only takes 200 seconds, and the traditional computer takes 10,000 years: Google's 53-qubit computer has a computing speed that is 53 times that of an ordinary computer.

Since quantum computing is so violent, how far is it from Bitcoin's SHA256 algorithm being violently cracked? The answer is: very far.

First of all, the definition of the term 'quantum supremacy' refers to the fact that a quantum computer can be much more efficient than existing classical computers in a program of practical value, provided that the program must be 'valuable' . But the Google quantum computer only simulated a very special computing scenario, which is of no value.

The second point is that Google's quantum calculator cannot guarantee that the result is correct. In fact, according to the theory of quantum computers, the calculation results of quantum computers can only be approximately correct at best. In contrast, the results given by classical computers are absolutely accurate and reliable. It is obviously not fair to compare the time it takes to compare the two. In fact, quantum computing with practical value must at least reach the blue area in the above picture. The current quantum computer is still far behind.

So far, quantum computers have proved to us their powerful executive functions, but not yet able to break cryptography. Similar to the creation of a nuclear hydrogen bomb by humans, it proves that nuclear fusion has powerful power, but this is still far from building a nuclear fusion reactor. For today's cryptographers, what needs to be done is to prevent the lapse of time and develop alternative primitives that are resistant to quantum attacks, such as various signatures, key exchanges, and zeros, before the day when quantum superiority truly destroys encryption technology. proof of knowledge etc.

In the current currency circle, there are two projects that do better in zero-knowledge proof and quantum-resistant signatures.

One category is anonymous coins, such as Grin and ZCash. The core value of these projects lies in their advanced encryption technology

The other category is some public chains that support quantum-resistant signatures. So far, only Hcash and IOTA have achieved anti-quantum characteristics among thousands of blockchain projects in the world. Compared with IOTA, HyperCash’s anti-quantum function has great advantages in compatibility, protection diversity, and reliability. . It is no exaggeration to say that HyperCash is currently the leading team in global blockchain anti-quantum. HyperCash's quantum-resistant signature has five advantages:

1) Compatibility: Before the emergence of anti-quantum computers, ECDSA signature schemes can still be used in cryptocurrency or blockchain systems, and Hcash is compatible with the ECDSA signature schemes of existing systems, so that it can be well integrated with the current mainstream The cryptocurrency trading platform is docked and provides the basis for subsequent support for cross-chain interoperability features;

2) Flexibility: Hcash supports two anti-quantum signature schemes (post-quantum signature schemes) that have been fully analyzed/assessed/demonstrated by the international cryptography community and are outstanding in terms of security or performance efficiency, which provides the system with more Greater flexibility and better security;

3) Security: The anti-quantum signature scheme supported by Hcash is not only provably secure in cryptographic theory (mathematically), but also has anti-side-channel attack characteristics in scheme implementation;

4) Efficiency: The combination of anti-quantum characteristics in the Hcash system and the new hybrid consensus mechanism makes the Hcash system have an absolute advantage in terms of throughput. For example: if the DILITHIUM anti-quantum signature scheme is implemented in the Bitcoin system, its TPS is at most 0.389 transactions per second, while the TPS of the Hcash system that realizes anti-quantum characteristics and a new hybrid consensus is about 150 transactions per second.

5) Applicability: Hcash's anti-quantum characteristics can be widely applied to existing cryptocurrency or blockchain systems.