After 20 years of studying cryptography, the "New Yugong Who Moves Mountains" reveals the secrets of blockchain cryptography

The mathematical principle of blockchain comes from the Byzantine Generals' Problem, but in ancient Chinese military, this problem can be solved with a tiger talisman. However, even with the current popularity of blockchain, in terms of transaction settlement, it is still necessary to overcome many cost and efficiency issues to establish such a safe and efficient trust mechanism.

Why can blockchain only process a few transactions per second now?

Sun Haidong, a member of the Chinese Cryptography Society and a partner of Qianhai Mengchuang Industry, said that we know that blockchain technology is the underlying technology of Bitcoin invented in 2009, but more deeply, blockchain technology is only created because of the growth of cryptography. "In other words, the cryptography used in blockchain technology today is the result of cryptography 20 years ago. After 20 years of evolution in information technology, software technology and cryptography technology, using an old cryptography result to promote the trusted blockchain that everyone wants today will definitely cause more problems. For example, why can blockchain only handle a few transactions per second now? What specific methods should be found to truly solve the problem?"

First of all, how are the passwords in the so-called blockchain, which we call the hyperledger, constructed? Sun Haidong said:

Today, the products of Hyperledger services are mainly a business-to-business, business-to-customer, and person-to-person service paradigm built on modern cryptography, software technology, network technology, and network society. Therefore, in the process of new media governance in this society, anyone in cyberspace who wants to participate in the Hyperledger's public accounting must first have a centralized authentication system.

"If there is no centralized authentication system to give you identity and identity recognition, the hyperledger will not form a humanistic ecology on the Internet." The current identity recognition on the Internet is the PKI (public key infrastructure) system, which has been used for more than ten years.

The second is policy management - PMI, or authorization management infrastructure, which relies on the support of PKI to provide access control and privilege management.

"It allows you to manage roles, because without role management there is no ecological cooperation. Once PMI is completed, it will enter the business module." Sun Haidong explained, but we know that there will be hash synchronization during the actual transfer process of the hyperledger. Why do we need to do two hashes? According to the famous cryptographer Wang Xiaoyun, it is because there is a problem with PKI.

"For example, when a banknote is issued, everyone can trade with each other after receiving it. If a distributed node in the Hyperledger publishes a public price transaction, we need to use two hashes to ensure the security of the hash result, to protect the publicity of the transaction content and the transfer process. This is the current blockchain trust technology. Therefore, blockchain technology only appeared when cryptographic technology was not mature."

In short, people should not be able to modify the history of the public hyperledger. Suppose there is a blockchain ABC. Any new node that receives this blockchain must be able to easily verify that transaction B did occur after transaction A, and transaction C did occur after transaction B. In cryptography, there is a very convenient tool to prevent data from being modified, which is hash. If C contains the hash value of B, then if anyone tries to send the modified B (which can be set to B') to the new node, the new node will immediately find that the hash value of B' does not match the record in C. So as long as the new node obtains the latest block in the blockchain, it can verify the legitimacy of the entire history.

As can be seen from the above, the amount of hash value calculation is very large. "In general, PKI identity authentication is used to ensure user trustworthiness and hashing is used to ensure that the plaintext data in the distributed database cannot be tampered with. This is how Bitcoin succeeded. But apart from Bitcoin transactions, if Hyperledger is applied to more distributed multi-identity participation scenarios, the original blockchain technology is definitely not enough."

Because Bitcoin is a relatively simple business, it does not require high levels of trusted technology and support systems. “So the problem lies in cryptography – there must be innovation in the cryptographic information security support system that supports the trusted medium of Hyperledger. Without innovation, it may be difficult for Hyperledger to truly and effectively enter the society with the existing blockchain technology.”

Cryptographic innovation makes up for the shortcomings of transaction performance

"Cryptology requires innovation, so our country has spent nearly 20 years developing distributed cryptographic authentication technology and related cryptographic technology systems." Sun Haidong's WeChat name is "New Yugong of Moving Mountains", and there is little information about his company on the Internet. "Cryptologists have two characteristics. One is that they are particularly crazy about technology; the second is that they are very careful in implementing technology and must use mathematical theories to repeatedly prove it."

After nearly 20 years, the team that Sun Haidong relied on obtained national approval for the market application of cryptographic technology and will be able to officially enter the market. Previously, one of the core members of the team also invented the country's "Commercial Cryptography No. 4", which was the first cryptographic technology that China publicly opened to the world. Its security has been recognized by the international community so far, and it has survived in the international cryptography community for 10 years.

"We hope to create a set of passwords like the RMB. Once the central bank issues us an identity certificate, any two people do not need to go to the central bank for exchange, just like paper money, using algorithmic transactions." With such a set of passwords, "we can use new authentication algorithms and eliminate the time spent on blockchain, because we have guaranteed identity recognition, identity authentication, transmission verification and transaction verification, so we have completed the innovation of a new cryptographic system."

If this is achieved, perhaps it will be like the ancient tiger-talisman authentication technology - one password for each object, one password for each person, and one password for each time.

The new era of Tiger Authentication technology can basically realize the true efficiency of Hyperledger and new blockchain technology, and implement a transaction process that can save the time of two hashes.

Of course, passwords cannot solve all problems. Yang Fan, co-founder of Bubi, a domestic blockchain technology company, said, "As a person with a background in security, I know the importance of passwords. But in fact, it is not only cryptography that drives blockchain innovation, but also the application needs in reality that drive the progress of underlying technologies, such as cryptographic algorithms."