OKX区块链60讲 | 第24集: What是跨链技术?

Hello everyone, I'm Xiao K. Today we're going to talk about: "What is Cross-Chain Technology"?

In our last lesson, we learned about sidechain technology—a technique that allows assets to move from one chain to another and back again. Cross-chain technology, covered in this episode, is essentially an upgraded version of sidechain technology. The difference is that the original one-to-one relationship between chains has become one-to-many. Simply put, cross-chain is a technology that enables value circulation between multiple chains.

Since cross-chain is an upgraded version of sidechains, it must have something more powerful. In addition to solving efficiency and scalability issues, cross-chain's main advantage is that it can solve the interoperability problem.

The so-called interoperability problem means that when blockchain applications are used in various fields, different industries and use cases require one or even multiple chains, and the assets on each chain can only circulate within their own chain. This causes different participants to become isolated, closed groups—like isolated islands that have difficulty communicating with each other. This clearly hinders the socialized circulation of value. Cross-chain technology is primarily designed to solve this problem.

Currently, there are four main methods for achieving cross-chain:

The first method uses a notary approach to achieve cross-chain. Its principle is as follows: It was originally proposed by Ripple Labs as the Interledger Protocol, which aims to connect different ledgers and enable collaboration between them. In other words, it serves as a bookkeeping system compatible with various blockchains and can accommodate their differences. Therefore, everyone can use this protocol as a unified payment standard, allowing different bookkeeping systems to achieve value transfer between each other through a third-party "connector" or "verifier."

It's similar to how, during the Spring and Autumn and Warring States periods, Qin Shi Huang unified the currencies and languages of all states. Once the standards are unified, value transfer between different chains naturally becomes possible.

The second method is relay. This approach is quite similar to sidechains—it establishes a new chain that connects with other chains, as if many chains share a common sidechain. Thus, each chain can use this new chain as an intermediary to indirectly achieve cross-chain functionality.

For example, if Chain A wants to make a cross-chain transfer with Chain B, with Chain C as their relay chain. Chain A first sends data to relay Chain C, which then performs data verification. After verification is complete, a success proof is sent to Chain A, and data is simultaneously sent to Chain B. After Chain B receives the data, it sends a receipt proof to relay Chain C. Once Chain B's operation executes successfully, it sends a success proof to relay Chain C. In this way, cross-chain transfers between different chains are achieved.

The third method is distributed private key control. This method is equivalent to establishing a bank within the blockchain world. However, unlike real-world banks where power is relatively centralized, this bank is in a state where both the decentralized network and users hold the private keys—users control private keys for managing their own assets while the decentralized network also holds them. Therefore, this bank operates under joint management by users and the decentralized network, making it more decentralized. Everyone can use it as infrastructure to freely exchange assets on different chains, which naturally achieves value transfer between chains.

The last method is hash locking. We will explain its principle in detail when we discuss the Lightning Network in the next lesson.

In summary, although there are many cross-chain methods, they all share one core objective: solving the problem of value islands. It is precisely because of cross-chain technology that chains are connected to each other, making the blockchain world so lively and prosperous.

Thanks to Teacher Cao Yin for his help and guidance on this episode.

Sina Weibo: @高等曹寅

"OKX Blockchain 60 Lessons" is a blockchain educational animated video series jointly produced by OKX and Sina Technology. Targeting users with zero knowledge of blockchain, it uses articles, educational animations, and other formats to vividly explain blockchain concepts through five major sections and 60 knowledge points, covering concepts, technology, and applications. The content of this episode was guided by Cao Yin, Managing Director of the Digital Renaissance Foundation.

Disclaimer

This article may contain product-related content not applicable to your region. This article is dedicated to providing general information and does not responsible for any factual errors or omissions. This article represents only the author's personal views and does not represent OKX's views. This article is not intended to provide any advice, including but not limited to: (i) investment advice or investment recommendations; (ii) offers or solicitations to buy, sell, or hold digital assets; or (iii) financial, accounting, legal, or tax advice. Holding digital assets (including stablecoins) involves high risk and may fluctuate significantly or even become worthless. You should carefully consider whether trading or holding digital assets is suitable for you based on your financial situation. For questions about your specific circumstances, please consult your legal/tax/investment professional. The information in this article (including market data and statistical information, if any) is provided for general reference only. Although we have taken all reasonable precautions in preparing this data and these charts, we assume no responsibility for any factual errors or omissions expressed herein. © 2025 OKX. This article may be reproduced or distributed in its entirety or used in excerpts of 100 words or less, provided that such use is for non-commercial purposes. Any reproduction or distribution of the full article must prominently state: "This article is copyrighted © 2025 OKX, used with permission." Permitted excerpts must cite the article name and include the source, for example, "Article name, [author name (if applicable)], © 2025 OKX". Some content may have been generated or assisted by artificial intelligence (AI) tools. Derivative works and other uses of this article are not permitted.

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