MEV：区块链隐私的隐藏威胁

中本聪是个天才，但在隐私方面，他却敞开了大门。现在，秃鹰正在大快朵颐。

Satoshi Nakamoto was a genius, but when it comes to privacy, he left the door wide open. Now, the vultures are feasting. The original blockchain and its many descendants are transparent, immutable, and decentralized. That might sound like everything you ever wanted from a financial system, but you’re wrong.

中本聪是个天才，但在隐私方面，他却敞开了大门。现在，秃鹰正在大快朵颐。最初的区块链及其许多后代都是透明的、不可变的和去中心化的。这听起来可能像是你想要从金融体系中得到的一切，但你错了。

Privacy is a vital component of any secure financial system. There’s an inherent contradiction between blockchain technology and privacy. The desire for privacy is essential, and the right to be forgotten is enshrined in law. Still, blockchain technology violates this principle with its very existence because it’s an infusible, yet permanent and public, data ledger.

隐私是任何安全金融系统的重要组成部分。区块链技术与隐私之间存在固有的矛盾。对隐私的渴望是至关重要的，被遗忘的权利是法律规定的。尽管如此，区块链技术的存在仍然违反了这一原则，因为它是一个不可熔的、永久的、公共的数据分类账。

Maybe you don’t care because the only information that anyone can see is a string of random letters and numbers, however, this has real-life implications for transactions on the chain.

也许您不在乎，因为任何人都可以看到的唯一信息是一串随机字母和数字，但是，这对链上交易具有现实意义。

Consider a potential example: You go to Uniswap to buy a token, place your order, execute…and receive significantly less of the token than you expected. You check the pair’s order history and find that a large buy was made just before yours, pushing the price up, with a hefty sell following after your order went through. You’ve just been “front-run,” and probably not for the first time. 

考虑一个可能的例子：您去 Uniswap 购买代币，下订单，执行……并收到比您预期少得多的代币。您检查了该货币对的订单历史记录，发现在您的订单之前进行了大量买入，推高了价格，而在您的订单完成后又进行了大量卖出。您刚刚“抢先”，而且可能不是第一次了。

Front-run? You might think: “I was an ace runner in school; no one’s beating me!” Let’s take a step back and explain what front-running is.

抢先跑？你可能会想：“我在学校是一名优秀的跑步运动员；我是一名优秀的跑步运动员。”没人打我！”让我们退一步解释一下什么是抢先交易。

What is MEV?

什么是MEV？

Maximal extractable value (MEV) refers to the maximum value a blockchain miner or validator can make by including, excluding or changing the order of transactions during the block production process.

最大可提取价值（MEV）是指区块链矿工或验证者在区块生产过程中通过包含、排除或更改交易顺序可以赚取的最大值。

Blockchain networks are immutable ledgers secured by a decentralized network of nodes known as “block producers.” In proof-of-work blockchains, this means miners. For proof-of-stake networks, this refers to validators. The block producers are responsible for regularly aggregating pending transactions into blocks, which are then validated by the entire network and appended to the global ledger. While blockchain networks ensure all transactions are valid (e.g. no double-spends) and new blocks of transactions are continually produced, there isn’t a guarantee that transactions will be ordered as they were submitted to the blockchain.

区块链网络是不可变的分类账，由称为“区块生产者”的去中心化节点网络保护。在工作量证明区块链中，这意味着矿工。对于权益证明网络，这是指验证者。区块生产者负责定期将待处理的交易聚合到区块中，然后由整个网络验证并附加到全局分类账中。虽然区块链网络确保所有交易都是有效的（例如没有双花）并且不断产生新的交易块，但不能保证交易在提交到区块链时会被排序。

As each block can only contain a limited number of transactions, block producers have complete autonomy in selecting which pending transactions are in the mempool. In this memory pool, block producers store unconfirmed transactions offchain, which they will include in their block. As a result, block producers have full autonomy to engage in rent-seeking behavior by extracting MEV with impunity. For instance, the cumulative value of MEV extracted on Ethereum reached $78 million in early 2021, which then shot up to $554 million by the end of the year. MEV extracted on Ethereum now stands at over $600 million.

由于每个区块只能包含有限数量的交易，因此区块生产者在选择内存池中哪些待处理交易方面拥有完全的自主权。在这个内存池中，区块生产者将未确认的交易存储在链下，并将其包含在区块中。因此，区块生产者拥有完全的自主权，可以通过提取 MEV 来从事寻租行为而不受惩罚。例如，2021 年初，以太坊上提取的 MEV 累计价值达到 7800 万美元，到年底飙升至 5.54 亿美元。目前在以太坊上提取的 MEV 价值超过 6 亿美元。

Problems and solutions around MEV 

MEV相关问题及解决方案

Thankfully, the last few years have seen the development of various methods to mitigate the problem of MEV. These fall into two buckets: new transaction ordering protocols and modifications to existing protocols that reduce the scope for manipulation.

值得庆幸的是，过去几年出现了各种方法来缓解 MEV 问题。这些分为两类：新的交易排序协议和对现有协议的修改，以减少操作范围。

One solution that takes the former approach is Fair Sequencing Services (FSS), which ensures that transactions are ordered relatively to reduce opportunities for front-running or reordering by miners and validators. One example is Chainlink’s Fair Sequencing Service, which uses decentralized oracles to maintain fair transaction ordering. Another such protocol is First-In-First-Out (FIFO), which processes transactions as they arrive at the mempool. This method offers a straightforward solution to maintain order integrity, minimizing the chance for miners to manipulate transaction sequences for MEV.

采用前一种方法的解决方案是公平排序服务（FSS），它确保交易相对排序，以减少矿工和验证者抢先交易或重新排序的机会。一个例子是 Chainlink 的公平排序服务，它使用去中心化的预言机来维护公平的交易排序。另一个这样的协议是先进先出（FIFO），它在交易到达内存池时对其进行处理。这种方法提供了一种简单的解决方案来维护订单完整性，最大限度地减少矿工操纵 MEV 交易序列的机会。

Recent: ‘Unlucky’ MEV bot takes out huge $12M loan just to make $20 in profit

最近：“不幸的”MEV 机器人借了 1200 万美元的巨额贷款，只是为了赚取 20 美元的利润

These approaches have a common goal: to create a fairer and more secure transaction ordering system and reduce the potential for manipulation. This objective is essential for building the trust necessary for decentralized ecosystems to go mainstream.

这些方法有一个共同的目标：创建一个更公平、更安全的交易排序系统并减少操纵的可能性。这一目标对于建立去中心化生态系统走向主流所需的信任至关重要。

MEV mitigation approach

MEV缓解方法

The block producers rely on visible transaction data to manipulate transactions for profit. Privacy protocols solve the issue, although the primary function has never been eliminating MEV.

区块生产者依靠可见的交易数据来操纵交易以获取利润。隐私协议解决了这个问题，尽管主要功能从来不是消除 MEV。

Ring Confidential Transactions (RingCT) obfuscates vital transaction details, including the transaction amount, sender and recipient. RingCT prevents miners from determining which transactions might be lucrative to manipulate, reorder or front-run. If specific details of individual transactions are made invisible, MEV extraction becomes virtually impossible, as miners are left blind to potential arbitrage or front-running opportunities.

环形机密交易 (RingCT) 会混淆重要的交易详细信息，包括交易金额、发送方和接收方。 RingCT 可以防止矿工确定哪些交易可能通过操纵、重新排序或抢先交易而获利。如果单笔交易的具体细节不可见，MEV 提取几乎变得不可能，因为矿工对潜在的套利或抢先交易机会视而不见。

Likewise, stealth addresses are another powerful privacy tool to mitigate MEV. They generate unique, one-time addresses for each transaction, hiding the recipient’s identity. Since the addresses are untraceable, miners cannot focus on high-value transactions, removing the incentive to prioritize or reorder them for personal gain.

同样，隐形地址是缓解 MEV 的另一个强大的隐私工具。它们为每笔交易生成唯一的一次性地址，隐藏收件人的身份。由于地址无法追踪，矿工无法专注于高价值交易，从而消除了为了个人利益而对它们进行优先排序或重新排序的动机。

MEV relies on the ability of miners or validators to see transaction data to manipulate transaction order or inclusion. Privacy-centric design targets miners

MEV 依赖于矿工或验证者查看交易数据来操纵交易顺序或包含的能力。以隐私为中心的设计针对矿工