Shulou(Shulou.com)05/31 Report--

This article mainly introduces "how does the new zero knowledge proof of block chain work". In the daily operation, I believe that many people have doubts about how the new zero knowledge proof of block chain works. The editor consulted all kinds of data and sorted out the simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "how does the new zero knowledge proof of block chain work". Next, please follow the editor to study!

First, let's take a look at what the general ZKP protocol does. Suppose you now have a public function f, a private input x, and a public output y. You want to prove that you know an x and get f (x) = y without revealing what x is. And, to ensure that the protocol is simple enough, you want its verification to be faster than calculating f itself.

Let's give an example:

F is a calculation that needs to be run for 2 weeks on an ordinary computer, but only 2 hours in the data center. You send this calculation to the data center (that is, run the code for f), and the data center will run and feedback the answer y through proof. You verify this proof in a few milliseconds and believe that y is actually the answer.

You have an encrypted transaction, and X1 in the table is my previous balance. X2 is your previous balance. X3 is my new balance. X4 is your new balance. You want to create a certificate in which the transaction is valid (specifically, the previous and current balances are positive, and the decrease in my balance offsets the increase in your balance). X can be a secret key pair, and f can be a function that contains a transaction with built-in public input, and as an input key, decrypts the transaction, completes the verification, returns 1 if it passes, and 0 if it fails. Y will be 1, of course.

You have a block chain similar to Etay Square, and you downloaded the nearest block. You want a proof that the block is valid and that the block is at the top of the chain, where any block on the chain is valid. You want an existing full node to provide such verification. X is the whole chunk chain, f is the function of block processing, verifies the validity and outputs the hash of the last block, and y is the hash of the block you downloaded earlier.

So what is the difficulty of these problems? As it shows, zero knowledge proof (that is, privacy) needs to be easily guaranteed; there are many ways to convert any calculation into, for example, a tricolor chart problem. the three colors of the chart correspond to the solution to the original problem, and then use the traditional zero-knowledge proof protocol to prove that you can get a valid chart color even if you don't disclose its information.

The more difficult part is to provide simplicity. Intuitively, it is difficult to prove the simplicity of the calculation because the calculation is incredibly fragile. If you have a long and complex calculation, then you need to be able to jump from 0 to 1 anywhere in the process, and in many cases, even a small mistake can lead to a completely different result. Therefore, it is difficult to know how you can make random samples of the calculation process, for example, in order to ensure correctness. Because, it is easy to miss "a very small part of the calculation". But with some great math methods, you can do it.

The overall feeling is that the protocols associated with these protocols are using the mathematical method of correction coding, which is often used to make the data fault-tolerant. If you have project data, you can use that data as line code, and then you can select four points in this line. Any two of these points are enough to reconstruct the line, so it gives you the other two points. And if you make even minor changes to the data, it guarantees at least three of your four points. You can also encode the data into a polynomial of 1000000 dimensions and select 2000000 points; any 1000001 of these points will get the initial data, so the other points, and any deviation from the data, will change at least 1000000 points. The algorithm here will make use of polynomials in this way to amplify the error.

If the original data is changed by 1 point, it will change a lot for the polynomial.

A simple example

Suppose you want to prove that you have a multi-item P, so that for x from 1 to 1 million, P (x) is 0.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.