由比特币及区块链基础设施服务公司Blockstream主导开发的Liquid网络近日正式上线。作为首个比特币侧链，Liquid旨在为交易所及交易者提供快速、保密及安全的比特币转账服务。

首批参与Liquid的成员涵盖了全球知名交易所、OTC服务商等数字货币行业内的23家公司，具体包括：Altonomy、Atlantic Financial、Bitbank、Bitfinex、Bitmax、BitMEX、Bitso、BTCBOX、BTSE、Buull Exchange、DGroup、Coinone、Crypto Garage、GOPAX（由Streami运营）、Korbit、L2B Global、OKCoin、The Rock Trading、SIX Digital Exchange、Unocoin、Xapo、XBTO以及Zaif。

在今日由Blockstream发布的新闻稿件中提到，Liquid除了为公司和个人提供更快的比特币交易服务外，还提供更多扩展功能，包括：

· Liquid原生的Liquid比特币（L-BTC）资产由双向固定比特币（BTC）支持，随时可以提现，使得终端用户可以在成员之间快速安全地进行比特币转账，两分钟内即可完成全部清算。

· Liquid的已发行资产为传统资产添加了类似比特币的功能，如法币代币化、数字奖励积分及经验证资产（比如金币），而不需要专门开发区块链或者钱包软件。

· Blockstream的保密交易技术保证了只有交易各方才能得知交易的金额及资产类型，提高了L-BTC及已发行资产交易的隐私性。

Liquid主要面向哪些用户？快速清结算和隐私保护是如何实现的？与其他的侧链项目又有什么区别？ Blockstream首席战略官缪永权（Samson Mow）向进一步解释了这些问题，以下为访谈全文：

8btc：能否详细介绍一下Liquid主要有哪些使用场景？面向的用户群体是哪些？

Can you tell us more about the main use cases of Liquid? What are your target audience?

Samson：The main use case for the Liquid Network is fast and reliable settlement times. If you trade Bitcoin, then you can do it more effectively with Liquid. Blocks on the Liquid blockchain are signed instead of mined, so they are generated at a predictable rate of 1 per minute. That takes the uncertainty out of Bitcoin transfers which are subject to variation in block times – sometimes you can get a confirmation in a few minutes, sometimes an hour. Liquid will allow traders to move funds between each other as well as exchanges far more rapidly.

Liquid的主要使用场景是快速及可靠的清算时间。如果你是比特币交易者，那么Liquid将让你更加高效。Liquid区块链上的区块不是挖矿得来的，而是签署的，因此他们的生成速度是可预测的，保持在每分钟生成一个区块。这就消除了比特币转账中的不确定因素，比特币转账到账时间取决于出块时间——有时候几分钟就确认了，有时候要等上一个小时。Liquid使得交易员能够将资金在彼此之间以及交易所之间更快速地转账。

8btc：与其他的侧链相比，Liquid有什么不同和优势？

What are the differences and advantages of Liquid compared to other sidechains?

Samson：The two other sidechain projects that I know of are RSK and Drivechains. Both seem to still be in testing or beta stages, with Drivechains at a much more experimental stage. RSK uses Ethereum’s EVM so it will likely have the same issues with smart contract security that Etheruem has. Liquid is production ready and is built on top of the battle tested Bitcoin codebase.

我所知道的两个侧链项目是RSK和Drivechains，这两个项目应该都还在测试或者beta阶段，而 Drivechains还处在更加试验性的阶段。RSK使用以太坊的EVM，所以RSK很有可能也会像以太坊那样出现智能合约安全问题。Liquid已经转备好进入生产阶段了，并且Liquid是建立在经过考验的比特币代码库之上的。

8btc：具体到交易所的应用场景，加入Liquid网络的交易所能够实现哪些以往没有的功能？这些服务收费吗？对普通用户来说，能有哪些使用体验上的改变？

When it comes to the use cases in exchanges, what features will be enabled for the exchanges that have join the Liquid Network? Will they be charged for these features? What are the changes in user experience for ordinary users?

Samson：Exchanges and members of the Liquid network will keep a balance of L-BTC and provide functionality for their users to swap between BTC and L-BTC. At first, exchanges may facilitate inter-exchange transfers using L-BTC without having to expose their users to actually handling L-BTC, which simplifies the experience for ordinary users. For example, a user on Exchange A would generate a Liquid address on that exchange, and withdraw to that address from Exchange B. Exchange B would deduct from the users’ BTC balance and send L-BTC to Exchange A, who would credit that user with BTC. So from an end user’s point of view, they just withdraw to a special address for near instant Bitcoin transfers.

交易所以及Liquid网络成员将会持有一定的L-BTC余额，并为他们的用户提供BTC和L-BTC相互兑换的功能。一开始，交易所可以使用L-BTC来进行交易所间的转账，而不需要用户自己使用L-BTC，这就让普通用户感到使用很简单。比如说，一名用户在甲交易所生成了一个Liquid地址，然后从乙交易所提现至这个Liquid地址。那么乙交易所就会从该用户的BTC余额中扣除相应金额，然后将L-BTC发送给甲交易所，甲交易所会将相应金额以BTC的形式充值到该用户账户中。所以对于终端用户来说，他们只需要提现到一个特别的地址即可享受近乎瞬时完成的快速比特币转账。

The Liquid Network collects transaction fees from sending and receiving L-BTC, but these fees pay for pegging out L-BTC back to the Bitcoin blockchain.

Liquid网络对发送和接收L-BTC收取交易费，但这笔钱将会用来支付L-BTC转回到比特币区块链上时所产生的费用。

8btc：针对发行资产这个功能，比如发行法币代币，与现有的各类稳定币相比有什么差别或优势？ 用Liquid发行资产有哪些适合的场景和用户？

Compared to the existing and stable currencies, what are the differences or advantages of Issued Assets, such as fiat tokens? Who or under what circumstances should one consider issuing assets with Liquid?

Samson：You could issue a stablecoin on Liquid using the Issued Asset functionality! There are major benefits to issuing assets on Liquid compared to other platforms. Tokens in Liquid are native to its blockchain, whereas tokens in say Ethereuem, are created through a complicated smart contract with security risk. Also, the Liquid Network is solely used for financial transactions and settlement, so you don’t have to deal with garbage data being added to the blockchain which can cause congestion – we see that happening on Etheruem which can be clogged up easily by digital kitties.

你可以在Liquid上使用已发行资产这个功能来发行一个稳定货币（stablecoin）！相较于其他平台，在Liquid上发行资产有许多好处。Liquid上的代币是区块链原生的，而其他平台，比如说以太坊上的代币则是通过一个存在安全隐患的复杂的智能合约创建的。此外，Liquid网络仅用于金融交易及清算，而不会有垃圾数据被添加到区块链上从而造成阻塞——以太坊就经常被电子猫咪产生的垃圾数据阻塞。

8btc：Liquid作为由Blockstream开发的联盟链，其他想要加入网络的用户需要符合什么条件才能加入网络？

Liquid is a federated chain developed by Blockstream. What are the requirements for a user to join the network?

Samson：In general we look for reliable and reputable companies to join Liquid. Liquid is a federation, so end users would access it through member exchanges and institutions. For the current federation members, we have some of the largest exchanges in the world like OKCoin, BitMEX, and Bitfinex, along with major OTC desks like DGroup, and leading market makers like XBTO and Altonomy. We also have several companies that joined Liquid to take advantage of our Issued Assets functionality – Atlantic Financial and SIX Digital Exchange (this exchange is launched by the owner of Switzerland’s stock exchange) are very keen to focus on token issuance and digital assets.

总的来说，我们希望可靠的信誉好的公司加入Liquid。Liquid是一个联合组织，终端用户通过成员交易所和机构来使用Liquid。目前这个联合组织拥有世界上最大的几家交易所，比如OKCoin、BitMEX以及Bitfinex，此外还有Dgroup等大型OTC交易台以及XBTO和Altonomy等世界领先的造市商。还有几家公司加入是为了使用我们的已发行资产功能——Atlantic Financial以及SIX Digital Exchange（这家交易所由Switzerland的证券交易所创立）都对代币发行及数字资产非常感兴趣。

8btc：Liquid是如何实现保密交易的？

How does Liquid achieve confidential transactions?

Samson：Confidential Transactions is a privacy technology created by Blockstream that blinds the amounts of all UTXOs, while preserving public verifiability that no transaction creates or destroys coins. It’s accomplished creating commitments where data is concatenated with a blinding factor (random number) and then hashed with the SHA256 hash function. As Liquid is a new blockchain, we could include functionality for Confidential Transactions – we also have Confidential Assets which adds privacy to Issued Assets within Liquid.

保密交易是一个由Blockstream发明的隐私技术，这项技术能够遮挡所有UTXO的金额，同时保证公众仍然能够验证在交易过程中没有生成也没有毁灭任何一个币。工作原理是将数据和一个遮挡因素（随机数）结合在一起，然后使用SHA256方程进行哈希值计算。Liquid是一个新的区块链，因而我们能够添加保密交易的功能。此外我们还有保密资产功能，这项功能为在Liquid上发行的资产添加隐私性能。

8btc：Blockstream的盈利模式有哪些？Liquid未来会成为盈利手段之一吗？

What are the profit models of Blockstream? Will Liquid become one of the means of profit in the future?

Samson：Blockstream has a revenue share from the Cryptocurrency Data Feed which we developed in partnership with ICE (the owner of the New York Stock Exchange). In terms of Liquid, Blockstream will collect a monthly maintenance fee from Liquid members, and we plan to offer additional services on top of Liquid which we can monetize, such as improved tools for managing and issuing digital assets.

Blockstream的盈利来源之一是我们和洲际交易所（纽约证券交易所的母公司）共同开发的加密货币数据简报。至于Liquid，Blockstream每月会向Liquid成员收取维护费用，我们也计划在Liquid中推出收费的附加服务，比如用于管理和发行数字资产的高级工具。