屏蔽 CSV：比特币隐私和可扩展性的新时代

今天的比特币发展主要集中在两个主要问题：（1）扩容和（2）隐私。对比特币的通常建议包括添加新的操作码和脚本工具。

Bitcoin development today focuses on two major issues: (1) scaling and (2) privacy. The usual proposals to Bitcoin involve adding new opcodes and scripting tools. But an old idea is coming back, one that could make transactions more private and peer-to-peer.

今天的比特币发展主要集中在两个主要问题：（1）扩容和（2）隐私。对比特币的通常建议包括添加新的操作码和脚本工具。但一个古老的想法正在回归，它可以使交易更加私密和点对点。

Right now, every Bitcoin transaction is broadcast to the entire network for verification. It’s an effective way to prevent double-spending, but it also means more information is exposed than is strictly necessary. This leads to heavier computational demands, higher costs, and a system that struggles to scale.

目前，每笔比特币交易都会广播到整个网络进行验证。这是防止双重支出的有效方法，但也意味着暴露的信息超出了严格必要的范围。这导致更重的计算需求、更高的成本以及难以扩展的系统。

But what if moving part of the transaction process client-side didn't just improve efficiency, but also unlocks a whole new era of privacy on Bitcoin?

但是，如果将部分交易流程移至客户端不仅提高了效率，而且还开启了比特币隐私的全新时代，结果会怎样呢？

In our recently published paper, Blockstream, in collaboration with Alpen Labs and ZeroSync, we introduce the Shielded CSV Protocol, an improvement on Client-Side Validation (CSV) that offers truly private transactions. This new protocol is a significant step towards enhancing the privacy of Bitcoin transactions and has the potential to increase transaction capacity from 11 per second to over 100 per second, through some additional measures we’ll cover in this blog post.

在我们最近发表的论文 Blockstream 中，我们与 Alpen Labs 和 ZeroSync 合作，介绍了屏蔽 CSV 协议，这是对客户端验证 (CSV) 的改进，可提供真正的私密交易。这个新协议是增强比特币交易隐私性的重要一步，并且通过我们将在本博文中介绍的一些额外措施，有可能将交易容量从每秒 11 笔增加到每秒 100 笔以上。

This post offers a high-level overview of the Shielded CSV Protocol, which aims to advance layer one blockchain performance while remaining fully compatible with Bitcoin. Developed by the combined minds of Jonas Nick, Liam Eagen, and Robin Linus. Here’s the backstory on Shielded CSV, and why it has the potential to change everything.

这篇文章对 Shielded CSV 协议进行了高级概述，该协议旨在提高第一层区块链性能，同时保持与比特币完全兼容。由 Jonas Nick、Liam Eagen 和 Robin Linus 共同开发。以下是 Shielded CSV 的背景故事，以及为什么它有可能改变一切。

Bitcoin Then and Now

比特币的过去和现在

The Double-Spend Problem: How Bitcoin Solved It

双花问题：比特币如何解决它

Before Bitcoin, it was widely believed that creating a reliable digital currency was impossible without a trusted middleman. The double-spend problem meant there was no way to ensure a “digital coin” couldn’t be spent more than once. It was a fundamental flaw that kept digital currency from becoming a reality.

在比特币出现之前，人们普遍认为，如果没有可信的中间人，就不可能创造出可靠的数字货币。双重支出问题意味着无法确保“数字货币”不会被多次使用。这是一个根本性的缺陷，阻碍了数字货币成为现实。

Then, in 2009, Satoshi addressed this problem by introducing the shared public ledger called the blockchain. Instead of relying on a single trusted authority, Bitcoin uses a network of nodes on a shared public ledger, where every transaction is recorded and verified. This system ensures that each coin is unique, making it impossible to spend the same coin twice.

然后，在 2009 年，中本聪通过引入称为区块链的共享公共分类账来解决这个问题。比特币不依赖单一的可信机构，而是使用共享公共分类账上的节点网络，其中每笔交易都被记录和验证。该系统确保每个硬币都是唯一的，因此不可能两次使用同一个硬币。

When a Bitcoin transaction is added to the chain, it follows this process:

当比特币交易添加到链上时，它遵循以下过程：

During validation, nodes verify that the coins exist, check the validity of the signature, and enforce the critical double-spend rule—making sure each coin is spent only once.

在验证过程中，节点验证硬币是否存在，检查签名的有效性，并执行关键的双花规则——确保每个硬币仅被花费一次。

The whole purpose of this ledger is to maintain order, showing clearly who owns which coins and when they moved.

这个账本的全部目的是维持秩序，清楚地显示谁拥有哪些代币以及它们何时移动。

The purpose of the ledger is to keep transactions in order, making it clear who owns what coins and when they were sent.

分类账的目的是保持交易有序，明确谁拥有哪些代币以及这些代币何时被发送。

Since its inception, Bitcoin’s developers keep coming back to the same question: is this really the best and most private way to handle transactions? How can we make this system leaner, more efficient, and more private?

自诞生以来，比特币的开发人员不断回到同一个问题：这真的是最好、最私密的交易处理方式吗？我们怎样才能让这个系统更精简、更高效、更私密？

A Privacy Problem: Public Transactions

隐私问题：公开交易

Bitcoin's biggest privacy challenge is that bitcoin transactions are out there in the open on the blockchain. Satoshi saw this vulnerability from the beginning. In the original whitepaper, he suggested a straightforward solution: users should create new keys for each transaction and avoid reusing addresses.

比特币最大的隐私挑战是比特币交易在区块链上公开进行。中本聪从一开始就看到了这个漏洞。在最初的白皮书中，他提出了一个简单的解决方案：用户应该为每笔交易创建新密钥并避免重复使用地址。

The idea was to make it harder to link transactions back to a single owner. But in practice, with all the advanced chain analysis methods available today, maintaining privacy is much harder than it seems. Even with new addresses, linking transactions and identifying patterns has become easier for those intent on tracing user activity.

这个想法是为了让交易更难与单一所有者联系起来。但实际上，随着当今所有先进的链分析方法的出现，维护隐私比看起来要困难得多。即使使用新地址，对于那些有意跟踪用户活动的人来说，链接交易和识别模式也变得更加容易。

In response, privacy-focused protocols like Zcash have introduced novel ways to conceal transaction details using more advanced cryptography and things like zk-SNARKs. But these methods come with significant trade-offs: transactions are larger, making the verification process for nodes more resource-intensive and expensive to verify.

作为回应，Zcash 等注重隐私的协议引入了使用更先进的加密技术和 zk-SNARK 等技术来隐藏交易细节的新方法。但这些方法伴随着重大的权衡：交易规模更大，使得节点的验证过程更加资源密集且验证成本更高。

A Communication Problem: Communication is Inefficient

沟通问题：沟通效率低下

In Bitcoin’s design, mining serves two fundamental purposes: (1) proof-of-publication for transactions and (2) providing a consensus on the order of transactions. However, Bitcoins’ system also intertwines these core functions with less essential tasks, like transaction validation and coin issuance.

在比特币的设计中，挖矿有两个基本目的：（1）交易的发布证明；（2）提供交易顺序的共识。然而，比特币的系统还将这些核心功能与不太重要的任务交织在一起，例如交易验证和硬币发行。

Across all blockchains, whether it’s Bitcoin, Ethereum, Zcash, or Dogecoin, the transaction process always looks the same: wallets sign transactions, broadcast them to the network, and full nodes validate them. But is validating every transaction directly on the blockchain really necessary?

在所有区块链中，无论是比特币、以太坊、Zcash 还是狗狗币，交易过程总是看起来相同：钱包签署交易，将其广播到网络，然后由全节点验证它们。但直接在区块链上验证每笔交易真的有必要吗？

We think there’s a better way. The idea traces back to a 2013 insight, when Peter Todd first mentioned Client-Side Validation. In this mailing list post he asks, ‘Given only proof-of-publication, and a consensus on the order of transactions, can we make a successful crypto-coin system? Surprisingly, the answer is yes!’

我们认为有更好的方法。这个想法可以追溯到 2013 年的一次见解，当时 Peter Todd 首次提到客户端验证。在这篇邮件列表帖子中，他问道：“仅考虑发布证明以及对交易顺序的共识，我们就能创建一个成功的加密货币系统吗？”令人惊讶的是，答案是肯定的！

Instead of requiring every full node to verify every transaction, CSV allows you to send coins with proof of their validity directly to the recipient

CSV 允许您将带有有效性证明的代币直接发送给收件人，而不是要求每个完整节点验证每笔交易