OKX Blockchain 60 Lectures | Episode 26: What is Segregated Witness?
Hello everyone, this is Xiao K, and today we're going to talk about: "What is Segregated Witness Technology"?
In the previous lesson, we explained that when Nakamoto originally designed Bitcoin, each block was limited to a maximum size of 1MB, which could only record a few thousand transactions. Early on, when the Bitcoin blockchain network had fewer users, this wasn't really a problem. However, as the number of Bitcoin users grew, this capacity became insufficient, causing frequent transaction congestion on the Bitcoin network.
To solve this problem, the Bitcoin community proposed two main categories of solutions: one involves off-chain solutions, such as the "Lightning Network" we discussed in the previous lesson, and the other addresses the problem on-chain. "Segregated Witness Technology," which we're covering today, falls into this second category.
Segregated Witness is, simply put, an on-chain technology for solving blockchain efficiency and scalability issues. Early on, the Bitcoin community's on-chain solution to transaction congestion was to directly increase the block capacity, since the congestion itself was caused by blocks being too small.
However, this raised a question: Nakamoto didn't set the block size limit to 1MB without reason. If block capacity were set too large, ordinary computers would face CPU overload during data packing, and over time, this would discourage new miners from joining. Therefore, adopting a block expansion approach could cause regular computers to fail to complete verification work, which would reduce the overall network's computing power and significantly compromise network security. As a result, block expansion has been a rather contentious topic.
Later, someone proposed: could this problem be solved on-chain without modifying the block capacity? This gave rise to the Segregated Witness solution.
The principle behind how Segregated Witness solves congestion is actually quite simple—it's essentially about "freeing up space." In a Bitcoin transaction record, there are two types of information: transaction data, such as who transferred how much to whom, and non-transaction data, such as someone's private key signature.
A block has only so much space and can hold limited data. So what Segregated Witness does is keep the transaction data in the basic structure while extracting non-transaction data and moving it to a new data structure. Nodes and miners performing verification work will still verify the signatures in this new data structure, but they won't count toward the 1MB limit. Think of it like organizing your closet—you keep the clothes you wear frequently and move rarely worn items to other places, thereby freeing up space. This allows the network to record more transaction data and improves Bitcoin's processing efficiency.
Additionally, Segregated Witness holds great significance in laying the foundation for the Lightning Network, making it easier to implement. By combining on-chain Segregated Witness with off-chain Lightning Networks, it can more comprehensively solve efficiency and scalability issues.
Overall, block expansion and Segregated Witness may have conflicting philosophies in some aspects, but ultimately their goals are the same—both aim to solve blockchain efficiency problems. This is precisely what makes blockchain interesting: it embraces different philosophies and seeks a better future from the unknown.
Thanks to Mr. Tan Chenhui for his assistance and guidance on the content of this episode.
Sina Weibo: @谭晨辉
"OKX Blockchain 60 Lectures" is a blockchain educational animated video series jointly produced by OKX & Sina Technology. Targeted at users with zero knowledge of blockchain, it uses articles, animated videos, and other formats to vividly explain blockchain concepts from the perspectives of concepts, technology, and applications through 5 major sections and 60 knowledge points. The content of this episode was guided by Instructor Tan Chenhui, CEO of CoinWorld.
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