What is Zero-Knowledge Proof (ZKP)? An innovative technology that protects privacy in the blockchain era

Let’s suppose David has the world’s best spaghetti Bolognese recipe. However, John wants to verify that David truly owns the recipe without knowing its specific details. This is where Zero-Knowledge Proofs (ZKPs) come into play. By leveraging ZKPs, David can prove the existence of the recipe without revealing any of its details.

This technology is not just a theoretical concept in cryptography; it is rapidly gaining attention as a practical tool that can be implemented in various privacy-sensitive areas such as blockchain, finance, and digital voting.

The Basic Operation of Zero-Knowledge Proofs: Understanding in Three Steps

The operation mechanism of zero-knowledge proofs consists of the following five processes.

First, the prover (David) and the verifier (John) agree on common cryptographic parameters and algorithms. Next, the prover cryptographically commits to the existence of the recipe without revealing its details. Then, the verifier presents a random challenge to the prover, who responds based on the committed information. Finally, the verifier checks whether the response aligns with the challenge and the commitment, thereby validating the proof.

Interestingly, these steps can be repeated multiple times, with each iteration increasing confidence. In essence, zero-knowledge proofs are built around a cycle of three phases: commitment, challenge, and response.

Why Are Zero-Knowledge Proofs Important? Balancing Privacy and Scalability

The reason ZKPs are gaining rapid importance is straightforward and fundamental. In modern society, there is a simultaneous demand for privacy protection and transparency, which can seem contradictory.

Especially as major tech companies accelerate data collection, the need for user anonymity and data protection has never been higher. At the same time, the inherent transparency of blockchain technology must be preserved. Zero-knowledge proofs are a highly valuable technology that can resolve this contradiction. They allow the validation of information authenticity without compromising privacy, serving as a key to achieving a balance between trust and confidentiality.

Major Types of Zero-Knowledge Proofs: The Difference Between SNARKs and STARKs

There are mainly two prominent implementations of zero-knowledge proofs.

ZK-SNARKs (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge) enable the prover and verifier to generate and verify concise proofs without interaction. They utilize elliptic curve cryptography, offering high efficiency, but require a trusted setup phase.

On the other hand, ZK-STARKs (Zero-Knowledge Scalable Transparent Argument of Knowledge) use hash functions instead of elliptic curves. The key differences are that STARKs do not require a trusted setup and are resistant to quantum computer attacks. Due to their promising future prospects, STARKs are considered to have a long-term advantage.

Implementing Zero-Knowledge Proofs: Deployment in Layer 2 Solutions

One of the most practical and significant applications of ZKPs is solving blockchain scalability issues. In particular, ZK Rollups serve as Layer 2 technology that significantly reduces the load on main chains like Ethereum.

ZK Rollups work by aggregating multiple transactions off-chain, compressing their validity into a single cryptographic proof (zk-SNARK), and recording this proof on the main chain. This approach dramatically increases transaction throughput and reduces user fees while maintaining the security features of the blockchain.

The operation of ZK Rollups involves three main steps: first, a large number of transactions are aggregated off-chain into a single data structure; second, a zk-SNARK proof of the validity of this aggregation is generated; third, this proof is submitted and verified on the main chain, reflecting the state transition and updating the ledger.

Notable zk-Rollup Projects Currently in Focus: Major Industry Players

Projects aiming to implement zero-knowledge proofs and zk-rollup technology are rapidly increasing in the blockchain industry.

zkSync is a project focused on Ethereum scaling, achieving significant improvements in transaction speed and cost reduction. Linea, developed by ConsenSys, adopts zkEVM technology to maintain compatibility with Ethereum while pursuing scalability.

Starknet provides solutions based on zk-rollup technology to address Ethereum’s transaction speed and cost issues. Polygon zkEVM leverages zk-rollup within the Polygon ecosystem to reduce gas fees and improve transaction speed.

Additionally, Scroll is a pure Ethereum Layer 2 project utilizing zk-rollup technology, offering native EVM compatibility and an easy-to-use scaling solution for developers.

These projects are integrating zero-knowledge proof theory into real blockchain ecosystems, continuously evolving while competing to enhance privacy, scalability, and transparency.