缺少的操作碼：為什麼比特幣 L2 需要 OP_CAT 才能成熟

比特幣 L2 是人們談論的話題，但它們的承諾尚未實現。比特幣的建造者還在等什麼？

Bitcoin Layer 2 (L2) protocols have been generating a lot of buzz recently, but their full potential has yet to be realized. Now, an important proposal could accelerate the development of the Bitcoin L2 landscape: the reintroduction of OP_CAT.

比特幣第 2 層 (L2) 協議最近引起了廣泛關注，但其全部潛力尚未實現。現在，一個重要的提議可以加速比特幣 L2 格局的發展：重新引入 OP_CAT。

This opcode, which was disabled early on in Bitcoin's history, could unlock new possibilities and pave the way for more advanced and trustless Bitcoin L2 solutions.

這個在比特幣歷史早期就被禁用的操作碼可以釋放新的可能性，並為更先進和無需信任的比特幣 L2 解決方案鋪平道路。

Let's dive into why this opcode is so crucial for BTC 👇

讓我們深入探討為什麼這個操作碼對 BTC 如此重要👇

What is OP_CAT?

什麼是OP_CAT？

OP_CAT, or "Operation Concatenate," is an opcode in Bitcoin's scripting language that enables the concatenation of two data elements.

OP_CAT，或“連接操作”，是比特幣腳本語言中的一個操作碼，可以連接兩個資料元素。

Initially proposed by Satoshi Nakamoto, OP_CAT was disabled in 2010 due to security concerns related to its original implementation, specifically potential denial-of-service (DoS) attacks caused by unbounded memory usage.

OP_CAT 最初由中本聰 (Satoshi Nakamoto) 提出，由於與其原始實現相關的安全問題，特別是無限制記憶體使用導致的潛在拒絕服務 (DoS) 攻擊，OP_CAT 於 2010 年被禁用。

However, the introduction of the Taproot upgrade in 2021 has addressed these original concerns. Taproot now enforces a maximum stack element size of 520 bytes, addressing the memory usage issue that led to OP_CAT's deactivation.

然而，2021 年 Taproot 升級的推出解決了這些最初的擔憂。 Taproot 現在強制最大堆疊元素大小為 520 字節，解決了導致 OP_CAT 停用的記憶體使用問題。

With this improvement and the renewed interest in Bitcoin development, thanks to Ordinals and Runes, a movement to reintroduce OP_CAT to enhance Bitcoin's scripting capabilities is gaining momentum, aiming to enable more complex transaction capabilities.

隨著這項改進以及人們對比特幣開發的新興趣，由於 Ordinals 和 Runes，重新引入 OP_CAT 以增強比特幣腳本功能的運動正在獲得動力，旨在實現更複雜的交易功能。

Are Covenants and Smart Contracts Different?

契約和智能合約有不同嗎？

One reason why OP_CAT is so interesting is that it can enable covenants, or spending conditions, on Bitcoin. Covenants and smart contracts are both mechanisms for controlling the flow of funds in a blockchain network, but they operate in distinct ways.

OP_CAT 如此有趣的原因之一是它可以在比特幣上啟用契約或支出條件。契約和智慧合約都是控制區塊鏈網路中資金流動的機制，但它們的運作方式不同。

Covenants

契約

Smart Contracts

智能合約

Why Does OP_CAT Matter for Bitcoin L2s?

為什麼 OP_CAT 對比特幣 L2 很重要？

OP_CAT would be crucial for advancing Bitcoin L2 solutions because it enhances the scripting capabilities needed for more complex and trustless Bitcoin infrastructure.

OP_CAT 對於推進比特幣 L2 解決方案至關重要，因為它增強了更複雜且無需信任的比特幣基礎設施所需的腳本功能。

Firstly, OP_CAT enables covenants, allowing for the construction of more advanced scripts. This is essential for creating the complex transaction conditions and functionalities required for L2 solutions.

首先，OP_CAT 支援契約，允許建立更高級的腳本。這對於創建 L2 解決方案所需的複雜交易條件和功能至關重要。

Moreover, with OP_CAT, users can unilaterally withdraw their funds from shared UTXOs, ensuring they can reclaim their assets without needing consent from other parties. This is also vital for trustless L2 protocols.

此外，透過OP_CAT，用戶可以單方面從共享UTXO中提取資金，確保他們無需其他方同意即可收回資產。這對於無需信任的 L2 協議也至關重要。

For example, CatVM, proposed by Taproot Wizards, would use OP_CAT to build a mechanism for locking and withdrawing funds in an L2 environment. It leverages OP_CAT's ability to concatenate data and verify Merkle tree branches, facilitating secure withdrawal processes.

例如，Taproot Wizards 提出的 CatVM 將使用 OP_CAT 建構在 L2 環境中鎖定和提取資金的機制。它利用 OP_CAT 連接資料和驗證 Merkle 樹分支的能力，促進安全提款過程。

OP_CAT also enables the creation of fraud proofs a la optimistic rollups to prevent double-spending and ensure the integrity of offchain transactions, another promising path for Bitcoin L2s.

OP_CAT 還可以透過樂觀匯總來創建詐欺證明，以防止雙重支出並確保鏈下交易的完整性，這是比特幣 L2 的另一條有前途的途徑。

Will OP_CAT be Activated?

OP_CAT 會被啟動嗎？

The reactivation of OP_CAT is currently being discussed in the Bitcoin community. While there is strong support for its potential benefits, the conservative approach to protocol changes in Bitcoin means that thorough testing and consensus-building are necessary steps before activation.

目前比特幣社群正在討論重新啟動 OP_CAT。雖然其潛在好處得到了強有力的支持，但比特幣協議變更的保守方法意味著徹底的測試和建立共識是啟動之前的必要步驟。

However, if the proposal to re-enable OP_CAT is approved, it could be implemented within six months to a year, depending on the community's consensus and the results of the testing phase.

不過，如果重新啟用 OP_CAT 的提案獲得批准，可能會在六個月到一年內實施，具體取決於社區的共識和測試階段的結果。

Furthermore, if OP_CAT is activated, projects like StarkWare are ready to begin development on top of it. StarkWare plans to use OP_CAT to bring zero-knowledge (ZK) scaling to Bitcoin, enabling advanced financial instruments and applications on the network.

此外，如果 OP_CAT 被激活，像 StarkWare 這樣的項目就可以在其之上開始開發。 StarkWare 計劃使用 OP_CAT 為比特幣帶來零知識 (ZK) 擴展，從而在網路上實現先進的金融工具和應用程式。

StarkWare’s involvement here highlights the broader ecosystem's readiness to capitalize on the enhanced capabilities that OP_CAT would introduce.

StarkWare 的參與凸顯了更廣泛的生態系統已準備好利用 OP_CAT 將引入的增強功能。

As the community continues to explore and test the possibilities around this proposal, the future of Bitcoin L2s looks promising and ripe with potential. At this point, reactivating OP_CAT seems like a matter of when not if!

隨著社區繼續探索和測試圍繞該提案的可能性，比特幣 L2 的未來看起來充滿希望並且潛力十足。此時，重新啟動 OP_CAT 似乎只是何時而不是是否的問題！