What is the next killer application we really need to bet on after ZK-Rollups?

With the dust settling on the "Airdrop Season" of leading projects such as zkSync and Starknet, zero-knowledge (ZK) technology has ignited both fervor and controversy within the community like never before. For the first time, millions of users' wallet addresses are directly linked to this arcane cryptography technology with real money. However, amidst the clamor surrounding valuation, volume, and airdrop rules, are we falling into a form of "winner's myopia"? Are we merely locking the imagination of ZK into the singular dimension of "making Ethereum faster and cheaper"?

As the market's attention is still focused on the fierce competition in the Layer 2 arena, another grand wave—the integration of AI and Crypto—is quietly rising. ZK is precisely the key technological bridge connecting these two super narratives. This article aims to penetrate the haze of the current ZK-Rollups hype and presents a core viewpoint: the ultimate battlefield of ZK technology is not to win the L2 war, but to build a trustworthy, permissionless digital reality that can defend personal sovereignty for the upcoming AI era.

(Photo from: @ayyyeandy)

ZK-Rollups: A great starting point, not the end point.

There is no doubt that ZK-Rollups are the most successful commercialization of zero-knowledge proof technology to date. It addresses the scalability problem in the "impossible triangle" that has plagued the blockchain world for years using an almost perfect Cryptography technique. By bundling hundreds or thousands of transactions off-chain (Layer 2) to generate a concise Validity Proof, which is then submitted to the main chain (Layer 1) for verification, ZK-Rollups have increased Ethereum's transaction processing capacity by several orders of magnitude without sacrificing security.

From StarkWare's StarkNet to Matter Labs' zkSync, and then to Scroll and Polygon zkEVM, the technical competition among major teams is almost entirely centered around "EVM compatibility" and "transaction costs (Gas Fee)." The market has responded enthusiastically, and capital has invested real money to express its preferences. This has created a kind of prosperity, but it has also led to a "tunnel vision"—we seem to take for granted that the mission of ZK is to make on-chain transaction experiences faster and cheaper.

However, if we broaden our perspective, we will find that limiting ZK technology solely within the framework of scalability is an underestimation of its revolutionary potential. Scalability is a necessary path, the infrastructure leading to the future; but it is not the future itself. It paves the way for us, but what truly captivates the imagination is the scenery that this path leads to.

Break out of the expansion city: The three high-potential battlegrounds of ZK

When we no longer see ZK merely as a "compression tool," its essence as a "trust tool" becomes apparent. This reveals three areas that are urgent to explode, and more in line with the spirit of Crypto fundamentalism:

1. Verifiable Computation (: Reshaping the trust foundation of data and computation

Imagine a scenario: a complex machine learning model or a sophisticated financial risk model running on a cloud server. How does it prove to you that its computation process is accurate and has not been maliciously tampered with? In traditional Web2 architecture, we can only choose to "trust" the service provider.

ZK technology has completely changed the game. Through zero-knowledge proofs, the party executing the computational task can generate a proof that certifies it has executed the computation entirely according to the preset program and has honestly returned the results. The verifier does not need to re-execute the entire time-consuming and labor-intensive computation process; it only needs to verify this lightweight proof to establish a mathematically level of trust in the results.

This is not just a technical show-off. It will unlock decentralized physical infrastructure networks (DePIN), decentralized science (DeSci), and a fairer digital advertising market. For example, the field of ZKML (Zero-Knowledge Machine Learning) that Modulus Labs is exploring allows the inference process of AI models to be verified, so users can be assured that the AI-generated results they receive have not been censored or manipulated. Projects like RISC Zero, by building a general-purpose ZK virtual machine (zkVM), enable any type of computation to produce ZK proofs, opening the door to decentralized and verifiable cloud computing. When the computation process itself becomes trustworthy and verifiable, we no longer need to rely on centralized brands or institutions as trust intermediaries, making a truly peer-to-peer, permissionless computing market possible.

2. Decentralized Identity )DID( and On-Chain Reputation: Build Your Web3 Native Passport

In the current Web3 world, our "identity" has been brutally simplified to a Wallet Address. This Address records our assets and transaction history, but it cannot carry our complex social relationships, professional achievements, or credit scores.

ZK-DID allows users to selectively prove their attributes without disclosing specific personal information. For example:

Prove your credit score is above a certain threshold to DeFi protocols to obtain better lending rates without exposing your entire asset situation.

Prove that you are a real, independent user in DAO governance voting without revealing your identity.

Prove to a gaming platform that you are over 18 years old without showing your ID number.

The ability of "selective disclosure" is key to building a Web3 ecosystem that can protect user privacy while establishing complex social collaborations. This is not a fantasy; Polygon ID has already constructed a complete set of open-source frameworks for this purpose, allowing developers to easily integrate ZK authentication features. Projects like zkMe focus on providing decentralized KYC solutions, where users only need to verify once to anonymously prove their compliant identity across the entire Web3 world. Even large-scale social experiments like Worldcoin utilize ZK technology to ensure that users' "proof of personality" is separated from their on-chain behavior, protecting personal privacy. This will give rise to a native on-chain reputation system, transforming our digital identity from merely a cold address into a rich, three-dimensional, and sovereign "soul."

3. True On-Chain Privacy: From Transparency to "Controllable Transparency"

The transparency of Ethereum is a double-edged sword. It guarantees the fairness and auditability of the system, but also exposes the financial status of all users to the light of day. Privacy coins (such as Zcash) have long demonstrated the power of ZK in transaction privacy, but their ecosystem is relatively isolated.

The trend of the future is to seamlessly integrate privacy features into mainstream smart contract platforms in an "optional" or "default" manner. Imagine that enterprises can perform confidential supply chain financing settlements on-chain; DAO organizations can carry out anonymous salary distributions; individual users can conduct private asset transfers.

In this sector, Aztec Network is the pioneer, aiming to bring a native privacy layer to Ethereum by building a cryptographic ZK-Rollup, allowing users to conduct confidential transactions within familiar DeFi applications. Furthermore, Layer 1 public chains like Aleo are designed for privacy from the underlying architecture, with the goal of creating a default private smart contract platform. This requires us to shift from the mindset of pursuing "complete transparency" to pursuing "controllable transparency"—that is, data is private by default, but owners can grant viewing permissions to specific parties (such as audit institutions) as needed and generate corresponding ZK proofs to verify compliance. This is the most profound transformation of ZK technology at the levels of finance and even social governance.

The success of ZK-Rollups is a tremendous victory for ZK technology at the level of "instrumental rationality." It efficiently addresses the most pressing pain points in the industry. However, the vast universe of Crypto ultimately needs to return to the exploration of "value rationality"—what kind of world do we really want to build with these powerful tools?

I firmly believe that the ultimate mission of ZK technology is to empower individuals with unprecedented digital sovereignty. It enables us to participate in the digital economy without sacrificing privacy, to verify the authenticity of the information we rely on, and to build a trust internet that is not defined by centralized giants, but rather guaranteed by mathematics and consensus.

Therefore, when we evaluate a ZK project next time, we may raise questions at a higher dimension: besides making transactions faster and cheaper, does it make our digital world more trustworthy? Does it give us stronger control over our identity and data? Is it contributing to a fairer and more protective future for individuals?

Betting on ZK is not just betting on a technology, but also betting on a future. And that future is much grander than the TPS and Gas fees we are discussing today.