Babbitt Interview | Author dialogue Bulletproofs: Money is the driving force encryption cryptography practices

Bitcoin and Ethagon Square and other cryptocurrencies have proven to have a place in the market after years of development. Bitcoin, which began with decentralized peer-to-peer trading, gained a first-mover advantage due to its transparency and fairness, while later private currencies such as Zcash and Monroe reflected the market's demand for different functions.

Monroe is considered a bitcoin in the privacy coin, which has both the decentralization of bitcoin and the privacy attributes. In October last year, Monroe ushered in a major upgrade to Bulletproofs through a hard fork. This technology can help it reduce its transaction capacity by 80%, and has now reduced the transaction cost of Monroe by 97%.

Bulletproofs is a short proof of zero knowledge. Simply put, this technology can not disclose any other information while proving the information that needs to be proven. Bulletproofs not only affects the privacy cryptocurrency market, it can even be applied to bitcoin, sidechain, private chains, and allows bitcoin exchanges to prove their solvency. Current mainstream currencies, including Litecoin and Ethereum, are seeking to deploy zero-knowledge proofs such as Bulletproofs.

As you can imagine, Bulletproofs is a breakthrough in zero-knowledge proof. Last week, in Shanghai I met Benedikt Bünz, one of the authors of the Bulletproofs paper, and the male god of thousands of programmers and technology enthusiasts.


(Benedikt sprouting)

With a small fresh face, Benedikt is already a Ph.D. He is the co-founder and chief scientist of Findora. He told us that Findora is a cool new project to reform the financial industry by looking for a balance between auditability and privacy.

In this conversation with Benedikt, we have a better understanding of Bulletproofs and zero-knowledge proofs; we learned about the polishing phase that a technology needs to go through in the process of code change; cryptography is not just a cryptocurrency. .

In order to let us understand a lot of technical concepts, Benedikt gave a lot of interesting examples, including "your predecessor" and "you are in prison." This is an article with a lot of examples. Benedikt gave us at least 12 "examples", "for example", "if", "for example". Want to know what he wants to explain? The following is the full text of the interview (there are editors who do not change the original intention):

8btc: As one of the authors of the Bulletproofs paper, let me talk about what Bulletproofs is.

Benedikt Bünz: Bulletproofs is a Zero Knowledge Proof (ZKP). A zero-knowledge proof can prove the correctness of something without giving extra information about why this is correct. For example, suppose I am a bank. I need to prove that I am solvable. I can prove (with zero knowledge) that I am solvable, and I don't need to disclose the customer's account balance and bank debt. Similarly, bitcoin exchanges can prove their solvency and do not need to disclose asset holdings or any other information.

8btc: When you created Bulletproofs, where do you most want to use it?

Benedikt Bünz: I think cryptocurrency and cryptocurrency trading will be a good application scenario. Bitcoin has a lot of great features, for example, you know that every transaction is correct, you don't need to trust anyone, it's completely decentralized. But there are also shortcomings. For example, every transaction is public. If you receive wages in the form of bitcoin, then everyone can see your salary, which is unrealistic. Especially in the financial sector, if I run a fund on the blockchain, I don't want everyone to see the fund's investment situation, which requires privacy, which is what I think is the zero-knowledge proof technology such as Bulletproofs. Where it should work. This type of technology ensures that only information that needs to be made public is disclosed. For example, I can prove the validity of a transaction without seeing the specific transfer amount. Fortunately, this technology has entered the deployment phase today and is becoming more pragmatic, which is what Findora wants to do.

8btc: You think Bitcoin needs privacy, right?

Benedikt Bünz: Yes. I think many people agree with this. Bitcoin may be useful as a speculative and hedging instrument, but cryptocurrencies such as Bitcoin must be private in order to be free from speculation and trading. The bank knows the amount of each transaction you send, but they won't make your deal public. Your predecessor will not know how much money you have transferred to, and of course you don't want them to know that your business competitors will not know your trading situation. Therefore, it is necessary to enjoy privacy.

8btc: Do you think Bitcoin is likely to use Bulletproofs?

Benedikt Bünz: Of course it is possible in theory. But I think Bitcoin (community) is very conservative and they don't want to change too much. So it may take a little while for Bitcoin to use Bulletproofs.

8btc: What is Supersonic just released by Findora?

Benedikt Bünz: I announced Supersonic at the time of the presentation. This is the latest breakthrough in Findora's proof of zero knowledge. There is a type of proof system called SNARKs, which has some great features. With SNARKs, you can not only do it. Zero knowledge proves that it also has advantages in terms of capacity expansion and compression. For example, I can prove to you that a block trade is correct with a short proof and it is very efficient to check. The final customer only needs to check this short proof. But the problem with SNARKs is that they need to be trusted to set up such a proof system that needs to be set up secretly and may contain harmful content. In order to discard some harmful content, you must trust someone, then the whole system may collapse, and there may be bad things like creating money out of thin air. The Supersonic we created is the first highly efficient SNARKs and does not require trusted settings. Now that you don't need to find someone you trust, you can set it up directly, which will be great.

8btc: What do you think about Halo, the recently released privacy program?

Benedikt Bünz: I think what Halo wants to do is very similar to Supersonic, but it doesn't have the effect of Supersonic. The focus is on technical differences. Halo doesn't need a trusted party, but it still requires a third party such as a helper (a third-party helper is responsible for compressing zero-knowledge proofs to achieve greater efficiency). Only in this case Halo is efficient and requires a lot. People go to implement a lot of different proofs. This is not strictly what we call SNARKs, and there are no related features. Supersonic contains these features. Halo has a lot of ideas, but there is still a lot of room for improvement.

8btc: Is there any trick to prevent bugs when technology becomes code?

Benedikt Bünz: This is a very important question. First, you need some experienced engineers, be very careful when deploying the technology, make sure that the code of each line is correct, otherwise the whole system or the entire blockchain may collapse. For example, Monroe conducted a code audit before deploying Bulletproofs, and many people, including me, participated in the code audit, which is very important. More importantly, the agreement itself must be simple enough, clean, easy to understand and easy to deploy. If it is a very complicated program or protocol – Halo is a more complex protocol, it is risky to deploy this protocol correctly. Therefore, a simple protocol can make things easier, and security proof is also very important, that is, mathematically prove that a certain protocol is correct, feasible, and safe. This is what we are doing, and it needs to be combined with many different things. work.

8btc: Does Supersonic have a security audit plan?

Benedikt Bünz: Of course, first we will submit Supersonic to the industry's top academic seminars, and the researchers will review the mechanism and check the correctness of the safety certificate. I hope everything is correct, I hope they can accept Supersonic. After that, in the output stage, there must be code auditing, otherwise no one will believe that it is safe.

8btc: Do you have a special favorite privacy currency?

Benedikt Bünz: I think there are a lot of interesting projects, but I think we are doing something new now. Findora is not concerned with privacy, but the privacy of financial services, such as hedge funds, investment funds or lending platforms. The lending platform can run on our underlying technology with privacy and auditing capabilities. As a result, regulators can ensure that lending platforms do not flee with money, but they do not need to look at the number of accounts and lending on the platform, so this is a balance between privacy and auditability.

8btc: Faced with the removal of privacy coins in many countries, what do you think of the future of privacy coins?

Benedikt Bünz: I don't know much about privacy. I only look at privacy money from an academic perspective. I think the key issue is the regulation. These privacy currencies may indeed be used for illegal activities, so regulators want to seek a balance between compliance and customer privacy. Balancing transparency and privacy is challenging.

8btc: If people don't want to pursue privacy, then no matter how the technology develops, they can't help. So how do you think people should be more aware of their privacy?

Benedikt Bünz: It’s too late when you realize that you need privacy. For example, due to privacy issues, suddenly you are in jail or your application is rejected, or someone is monitoring you. I believe that it is imperative to realize privacy. Users' pursuit of privacy should not be a lot of effort. This should not be their burden. In addition, in some application scenarios, users are very clear that they need privacy, such as me. I think no one wants to disclose their salary on the blockchain so that everyone can see that they may only want to announce the transaction object, not the transaction amount. So I think that in most cases people's need for privacy is unconscious.

8btc: Cryptography is not limited to cryptocurrencies. Can you talk to us about cryptography?

Benedikt Bünz: Of course, we need cryptography every day. You should use cryptography when you visit every website. The https on the address bar is cryptography. To ensure that you are connected to the correct website, make sure your data provider cannot read the encrypted data you send, such as your bank information, only the bank and you can see the relevant content. I think that the operation of the Internet today is inseparable from cryptography. Zero-knowledge proof belongs to the new cryptography, modern cryptography, which has many applications that are exciting. For example, if you want to do DNA testing, you need to study different databases based on different DNA data, and hospitals holding these databases may not want to disclose all the information. With cryptography, we can get the research output after completing the study, that is, how many people have these DNA characteristics, and do not need to publish all the basic DNA information. This is a very cool thing. You can also conduct a private vote. During the election process, all the votes will not be announced and only the final election results will be announced. There are many cool applications for cryptography. I hope that we can see more applications in the future, and cryptocurrency is the driving force for the top cryptographers to practice. This field is exciting.

Reporter: Wendy