Getting started with blockchain | New advances in quantum computers, is the wallet safe?

Author / JackyLHH

Produced / Vernacular Blockchain (ID: hellobtc)

Almost every once in a while, "breakthroughs" in quantum computers are coming out. This has caused panic among some users in the industry: the advent of quantum computers will crack Bitcoin's encryption algorithm, and the crypto world is about to collapse.

No, recently American company Honeywell officially announced that it has made breakthrough progress in the field of quantum computing, which will improve the performance of quantum computers. In addition, Honeywell also claims that the world's most powerful quantum computer will be released in the next three months.

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Quantum computers, source: MIT Technology Review

This has caused many crypto asset holders to worry about whether crypto assets such as Bitcoin are still safe and will they be easily cracked by quantum computers?

Let's start with the conclusion here: at least at this stage you don't need to worry, even if the general-purpose quantum computer appears in the future, Bitcoin will not necessarily be "killed".

Next, we talk about related reasons.

There are two main types of encryption algorithms used in Bitcoin: Elliptic Curve Digital Signature Algorithm (ECDSA), and SHA256 hash algorithm. Among them, ECDSA is mainly used for private key and public key generation; SHA256 is mainly used for public key generation wallet address and proof of work (PoW) during mining .

Quantum computers threaten the security of ECDSA. In 1994, the Shor algorithm designed for factorization was designed. A sufficiently strong quantum computer (hardware) plus the Shor algorithm (software) can be used to crack the private key by using the public key.

Of course, this process of cracking a quantum computer also takes a long time. Moreover, the development of quantum computers is not smooth, and the performance at the beginning is not so powerful.

Even if a quantum computer is powerful enough, there are ways to protect your own Bitcoin: Use only one-time Bitcoin addresses at a time.

This is due to the fact that when Satoshi Nakamoto originally designed Bitcoin, he did not directly use the public key as the payment address of Bitcoin. Between the public key of Bitcoin and the corresponding address, SHA256 encryption is performed, and currently there is no algorithm that can effectively crack SHA256.

For example, if Dabai needs to transfer 1BTC to Xiaohei, and Dabai's wallet address has 3BTC, as long as he transfers the bitcoin change address to a brand-new bitcoin address with his own private key . In this way, during the transfer, 1BTC entered Xiao Hei's address, and the changed 2 BTC entered the new white address. Regarding the change mechanism and UTXO model of bitcoin, you can read the tweet before the vernacular blockchain, " Without UTXO, Bitcoin may not run so stably for 10 years ."

When querying this transaction on the blockchain browser, you can see the address that Dabai transferred out and the corresponding public key, the address of Xiaohei, and the new address for change. Since the outbound address is used up and discarded, there is no BTC in it, so even if you see the public key, it is okay to crack the private key with a quantum computer.

As for the exposed address of Xiaohei and the new address for change, the quantum computer lacks an algorithm that can effectively crack SHA256, so it cannot crack the public key through the address, so it is safe.

Mining machine, source: www.hellobtc.com

Will the quantum computer have an impact on Bitcoin mining?

Computers now comply with Moore's Law, which means that the density of a computer chip's transistors doubles every 18 months, and its computing power doubles. But in recent years, the size of transistors has gradually approached the physical limit, the exponential growth of computing power has slowed, and Moore's Law has gradually failed. What makes a quantum computer powerful is that it is growing at a double exponential rate, that is, the growth index of computing power is also exponential. This allows traditional computers to take tens of thousands of years of computation, and quantum computers can be completed in a short period of time.

However, all quantum computers can do is reduce the calculation time drastically. It still takes time to calculate.

We mentioned earlier that there is currently no algorithm that can effectively crack SHA256, so when using a quantum computer to mine bitcoin, you can only find random numbers one by one to try like other mining machines. It is just that the quantum computer has a faster operation speed. It's fast. Bitcoin has a difficulty adjustment mechanism. It can counter the increase in computing power from quantum computers by adjusting the difficulty. It can also increase the difficulty of mining by upgrading the SHA256 algorithm (such as upgrading to SHA384, SHA512).

It should be noted that the above discussions are based on the premise that "quantum computers are very mature and inexpensive."

The reality is that quantum computers are still in the laboratory stage. At present, quantum computers can only perform single, highly technical calculations, and it will take several years to use them to solve practical problems. So far, no universal quantum computer has appeared, and reliable dedicated quantum computers have not yet come out.

One foot high and one foot high, while the quantum computer is moving forward, the encryption algorithm will continue to improve.

In the "Get" Lecture 30 of Dr. Cryptography, the well-known popular science author Dr. Zhuo mentioned the seventh-generation encryption method against quantum computers- quantum encryption .

Different from other encryption methods, quantum encryption uses not only mathematics but also quantum theory in physics. Quantum computers are also unlikely to be cracked, because if they are cracked, they would violate the basic principles of quantum mechanics.

After reading this article, are you still worried about the crypto assets in your hand? Welcome to share your views in the comments area.

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