In addition to scalability, there are many use cases for zero-knowledge proofs in Web3.

2023-02-17 22:00

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Zero-knowledge proofs can also be applied to off-chain computation, cross-chain bridging, asset security, user authentication, and other areas.

Original Title: "Beyond Scalability, There Are Many Use Cases for Zero-Knowledge Proofs in Web3"

Original Author: TinTinLand

In 2022, due to the progress of ZK-Rollups in the Ethereum field, Zero-Knowledge Proof has become the annual buzzword of Web3. Some even predict that the engine of the next bull market will be Zero-Knowledge Proof, and claim that the importance of Zero-Knowledge Proof to Web3 is comparable to Bitcoin's introduction of blockchain concepts and Ethereum's introduction of smart contracts.

What gives zero-knowledge proof such strong development potential? Perhaps we should start with the development of Web3. Web3 aims to transfer network ownership to its users through a decentralized network. However, current Web3 seems to only bring a user-centric value system, and there are still many problems that need to be solved before its vision can be realized. Privacy and security are key issues it faces.

Web3 networks are designed to allow users to interact with decentralized networks, avoiding the drawbacks of centralized networks in Web2 such as data leaks, privatization of data, and centralization. If you are running a full node, you will have complete and mathematically guaranteed cryptographic security. However, running a full node requires expensive hardware and maintaining a connection to a large blockchain of 100GB.

Obviously, current encryption clients cannot handle such requirements. Therefore, Web3 still relies heavily on trusted centralized intermediaries to connect Web3 decentralized networks, which seems to contradict the vision of Web3. How to ensure privacy and security in a decentralized network environment in a decentralized way? Zero-knowledge proof technology cleverly solves this problem. In addition to network security, there are many use cases for zero-knowledge proof, and this article will introduce its use cases in the encryption industry.

What is Zero Knowledge Proof?

Before introducing the use cases of zero-knowledge proofs in Web3, let's quickly understand the principle of zero-knowledge proofs. Zero-knowledge proofs are a type of cryptography that allows one person (the prover) to prove to another party (the verifier) that certain details are true without providing any additional information.

Zero-knowledge proof requires the following three key requirements:

Integrity: If the statement is indeed true and both users are correctly following the rules, then the verifier will not need any additional conditions to complete the verification.

Reliability: If a statement is false, the verifier will not be convinced under any circumstances. This method uses probability checking theory to ensure that no errors occur.

Zero knowledge: means that the person verifying the information cannot know any information other than whether the assertion is correct.

There are two main types of zero-knowledge proofs:

Interactive zero-knowledge proof requires the prover to perform a set of tasks or operations to prove to the verifier that they possess specific information. Most of the tasks required to pass an interactive zero-knowledge proof typically involve mathematical probabilities and the like. The prover and verifier do not need to communicate with each other to make a non-interactive zero-knowledge proof effective, and verification will take place later. Such special zero-knowledge proofs require additional computation or programs.

Zero-Knowledge Proof Use Cases in Web3

Although zero-knowledge proof technology was developed as early as 1980, it has not been widely used due to technical difficulties. What benefits can zero-knowledge proof bring to the development of Web3? Let's take a look at some technical use cases.

Off-chain computing

With more and more applications being deployed on Ethereum, the slow transaction processing speed and insufficient network scalability on Ethereum have become important obstacles to its development. Building a Layer2 network and transferring computational processing off-chain have become important solutions to the current problems. ZK-Rollups is one of the solutions highly recognized by the Ethereum community. ZK-Rollups includes Starkware and Zk-sync, which are scaling projects.

Scalability is the most common use case of zero-knowledge proofs in Web3. Currently, there are also solutions that combine scalability and privacy, such as Aztec and StarkNet, which are privacy Layer2 public chains. Interested developers can learn more in the article "A Brief Discussion on the Current Situation and Future of Privacy in Layer2".

Interchain Bridge Connection

With the expansion of the public chain ecosystem, it is difficult for Ethereum to dominate the market, and the demand for cross-chain interoperability is increasing. However, the security of using bridges for cross-chain transactions cannot be guaranteed. Therefore, many projects will start using zero-knowledge proofs to achieve interoperability. This includes Wormhole, Polymer, and ZKBridge, which are building trustless cross-chain protocols based on zero-knowledge proof technology, and will change the inability to communicate due to IBC light clients not being able to run on ETH. Zero-knowledge proofs will also greatly improve the security of encrypted bridges to enhance the security of cross-chain interoperability.

On-chain games

Take "Dark Forest" as an example, this is a game inspired by Liu Cixin's "Three-Body" based on zero-knowledge proof. As a strategy game, many conspiracies in the game come from the concept of hidden information or information asymmetry. The entire Dark Forest universe is infinite, filled with thousands of opposing players, robots, scripts, smart contract players, and so on. However, after joining the universe, a single player can only access a small part of the entire universe map, which is exactly what gives "Dark Forest" its soul. How to achieve "hiding" part of the information on a blockchain where all information is public and transparent, this is exactly what is achieved based on zero-knowledge proof, to "hide" information that is not to be disclosed or requires triggering conditions.

Asset Security

Blockchain technology not only ensures that our assets are only processed by ourselves (non-custodial), but also stored in multiple nodes for reduced asset risk. Zero knowledge also helps to further improve the security level of Web3. In secure design, mathematical verification is used instead of probability theory. Zero knowledge reduces potential risks by adopting validity proof, which ensures the accuracy of information. Specifically:

The only person who can decipher encrypted information is the user; if the verifier is forged, the final root obtained will be different, and the verifier will refuse to accept it;

Even if all validators and verifiers collude, due to the availability of blockchain data, account status can still be rolled back and corrected;

When using zero-knowledge proofs, additional checks and reinforcement mechanisms are usually employed.

Authentication

Personal encryption identity can be confirmed through zero-knowledge proof. Zero-knowledge proof allows users to verify their identity to the system without revealing their complete personal information. For example, when you log in to an account, you need to enter a username and password, but if you use zero-knowledge proof technology, you only need to provide a ZK Proof, and the platform will never be able to calculate your real password, completing personal identity verification without revealing sensitive personal data.

Document Sharing

We often face the need for data sharing on the internet, but during the sharing process, we may encounter problems such as information loss and interception. When zero-knowledge proof is combined with blockchain technology, data can be encrypted and fragmented, not only ensuring transmission security, but also giving users the right to manage certain blocks and the information contained within them, thereby granting access permissions to certain users, while unauthorized users cannot access your shared documents.

Storage Protection

Decentralized storage, as one of the three pillars of Web3, is crucial for the development of the industry. Zero-knowledge proof can provide better protection for storage security by utilizing algorithms to set corresponding protocols, encrypting storage units and their protocols, and even setting encryption protection in access channels, taking the security of Web3 cloud storage to the next level.

* Disclaimer: This article should not be regarded as, nor is it intended to provide, any investment advice.

Zero-knowledge proof technology still has a long way to go

Aside from scalability and privacy use cases, the use cases for zero-knowledge proofs are very broad, and its role in Web3 is becoming clearer. Currently, many projects have begun to use this technology in practical applications. According to Messari's statistics, a number of projects in the most widely applied extension fields of zero-knowledge proofs will reach a critical period of development in 2023, such as Scroll, Polygon zkEVM, and other mainnet projects. In the article "L2 Projects Testing Network Launched in the New Year Sprint", recently launched testing networks for zero-knowledge proof projects are also introduced.

However, we need to recognize that although zero-knowledge proofs have broad application prospects and many fields in Web3, the performance issues of their proofs have not been properly resolved. Currently, many teams are working on hardware acceleration, but this hardware acceleration is only partially responsible for effective proof. Optimization is still needed at the algorithm level, software level, and other aspects.

Given this, the effective use of zero-knowledge proofs this year will appear in small-scale applications, making it difficult to achieve large-scale widespread use. After DeFi, zero-knowledge proofs still have a long way to go to become the engine of the next bull market. We hope that more Web3 developers will dare to challenge and overcome its technical challenges based on the prospect of zero-knowledge proofs, and promote application practice through technological progress.