香港圆桌会议AMA—对话Adam back内容记录

2016年2月29日，在持续近十天关于香港圆桌会议的争论后，在论坛进行了一场主要面向中国社区用户的AMA。Adam back，比特大陆CEO吴忌寒，BTCC COO缪永权参与了这次AMA，在持续近4个小时的时间里耐心解答了中国社区用户提出的每一个问题。

提问者众多，提问方式和问题涉及范围也非常广泛，我们尽可能呈现原貌。由于篇幅过长，我们将三位的回答分为三篇整理呈现给大家。

再次感谢三位嘉宾，在面对许多尖锐的提问下，依然以宽容的态度耐心解答。以下为AMA中针对Adam back的提问和回复内容记录。

为什么一定要达成扩容共识？如果在扩容区块大小问题上没有达成共识会怎么样？

Bitcoin is a user currency and operates by miners, exchanges, ecosystem companies and users collaborating. It is important to have consensus on changes to Bitcoin as it is necessary for the whole ecosystem to upgrade together and be in widespread agreement.
比特币是去中心化的货币，比特币社区包括矿工、交易所、用户等。比特币未来的发展需要获得社区广泛的支持以达到共识。

Satoshi设计了一个很好地机制，让算力投票来表达共识。为什么要人为阻挠Classic矿池的开启来实现Satoshi设计的算力投票？

Bitcoin is a user currency and works by collaboration between miners, exchanges, ecosystem companies and users. Many miners and companies consider that the soft-fork with segregated witness is a safer and faster upgrade. Around 80% of miners by hashrate indicated support for this plan and the four largest bitcoin exchanges. You can read their joint statement on collaborating to upgrade bitcoin scale here 

比特币是用户的货币，通过矿工、交易所、企业生态和用户之间的合作而起作用。许多矿工和公司认为，带有隔离见证的软分叉是更安全和更快捷的升级。大约80%的算力以及4个最大的交易所都支持这一计划。
你可以在此看到他们关于比特币拓展性升级的联合声明。

Core最近发布新软件。这款软件有哪些功能和改进？

The new version included 7x faster signature validation which is important for miners and nodes and for bitcoin to scale to more transactions per hour.
Also much faster block assembly for miners which reduces orphan blocks and so improves profit.
You can read more about it here.新版本包括快7倍的签名验证，这对于矿工和节点扩展到更多的每小时比特币交易很重要。
也比矿工区块组合更快，减少孤块和提高效益。
你可以在这里了解更多：

https://bitcoincore.org/en/2016/02/23/release-0.12.0/

你迫使员工不使用classic这件事是真的吗？

No definitely not true. Bitcoin is a user currency, and so it is important that any changes should be in the interests of users. To ensure this, it is important that Bitcoin proposals are subject to independent review, and in Blockstream we created employment contracts guaranteeing Bitcoin developers independence very intentionally because we did not want any company to have control of Bitcoin (including Blockstream).

不，这绝不是真的。
比特币是一种用户货币，因此任何变化都应该由用户的利益为导向。
为了确保这一点，对比特币相关的一些提案进行独立审查是十分重要的。在Blockstream，我们有意的设计了一些合同来保障比特币核心开发者的利益，因为我们不希望任何企业能够控制比特币（包括Blockstream）

Blockstream President Adam Back为啥要改签名，隔离验证交给这公司大家放心吗？

This is written about here https://www.reddit.com/r/btc/comments/46s54r/why_has_blockstream_omitted_putting_their/d0d20b9

Segregated Witness is developed by several developers the main ones, only one of whom, Pieter Wuille, works for Blockstream. Johnson Lau (individual from HK), Eric Lombrozo (CEO ciphrex) and many other developers worked on integrated segregated witness into libraries and wallets and reviewing the code and design.

这里有一部分关于这个问题的解释。

隔离见证是由几个主要的开发人员开发的。其中已有一个Pieter Wuille是为Blockstream工作的。Johnson Lau、Eric Lombrozo和很多其他的开发人员都在为代码的设计和Review、隔离见证对于库和钱包的继承而努力。

请介绍一下blockstream公司，目前有多少人，公司开发的目标是什么？ 将来公司的商业模式是什么？盈利点在哪里？

Blockstream’s mission is to extend Bitcoin to support different types of transactions for financial and other applications using sidechains. Sidechains offer a general extension mechanism allowing anyone to extend Bitcoin in an opt-in way. Examples of companies developing sidechains include rootstock and hivemind, both projects developed by other companies. Blockstream also developed the elements sidechain and the liquid sidechain. Blockstream has about 30 employees. Blockstream business model is to provide services and products delivering value to users and companies in the Bitcoin and finance areas.
blockstream的使命是扩展比特币的适用范围，使其能够通过侧链来支持金融或其他领域中各种不同类型的交易。侧链为所有人提供了一个可选择的机制来扩展比特币。侧链的一些实例有Rootstock和Hivemind，这两个都由其他公司开发。Blockstream也开发了一些侧链元素和Liquid侧链。Blockstream有大概30个员工。Blockstream的商业模式是为用户和比特币、金融行业内的企业提供有价值的服务和产品。

What’s the weighing behind the July 2017 deadline? is it possible to make it happen by the end of 2016?

The plan involves 3 stages. The plan is that the first scaling upgrade using segregated witness will be ready by April 2016, and a further upgrade to reduce transaction sizes (to squeeze more transactions into a block) later this year. From the first two upgrades there should be enough excess capacity to accommodate transaction growth through to 2017 when the 3rd hard-fork stage will activate.

For safety it is important that there is widespread agreement from miners, exchanges, ecosystem companies and users who must all upgrade for hard-fork upgrades. There are many services, pools, users and ecosystem companies that must upgrade before activation.

In addition, Jul 2017 is the latest for the hard-fork, it maybe possible sooner, using a different type of fork, if there is widespread agreement from users, miners, exchanges and ecosystem companies to do that.

这个计划一共有3个阶段。第一个使用隔离见证的扩展性升级将在2016年4月准备妥当，并在今年内进一步升级以减少交易的大小（以在同一个块中打包更多的交易）。通过这两个升级，在2017年第三阶段的硬分叉启动时，增加的产能应可以适应交易的增长。

为了安全起见，需要有一个矿工、交易所、企业生态链和用户之间广泛承认的协定，大家全都要升级至硬分叉。在升级之前，有很多服务、矿池、用户和企业生态需要提前升级。

此外，硬分叉升级最迟应在2017年7月启动，它也可能会提前，在用户、矿工、交易所和企业生态的广泛认同下使用一种其他形式的分叉。

为什么不马上实现一个共识的2M硬分叉，再仔细安排SW的验证和部署？

Segregated Witness is an alternative to a hard-fork and also provides similar scale. The reason to do SW first is that companies and users would like scale improvements to be available, and SW can be done sooner and more safely than a hard-fork. Also it becomes safer to do a second upgrade hard-fork after SW with the efficiency improvements that SW adds.
隔离见证是除硬分叉外的另一选择，其所提供的规模也近似于硬分叉。之所以先进行隔离见证是因为用户与公司都希望先达到规模上的改进，对此，隔离见证相对于硬分叉更快更安全。在有了隔离见证的效率提升之后再实行硬分叉的升级，更能加强安全性。

请问为什么国外矿工转到Classic的积极性比国内的高？是因为国内更注重挖矿，而国外更注重应用吗？如果块链满了以后对目前做比特币支付的影响很大，你们是否考虑帮助他们，以及如何帮助他们？

The plan is to increase scalability as fast and safely as possible so that many new users can enjoy the great features of Bitcoin. Scale involves many factors including network bandwidth, network latency, CPU overhead and memory. The Bitcoin 0.12 release includes 7x faster signature validation which allows bigger blocks and many other scale related performance improvements. The Bitcoin developers have been hard at work on scaling features for many months, the first of which is segregated witness. There multiple additional scale improvements that come after segregated witness, including Schnorr signatures, that can greatly compress transactions, to get more transactions in the same space as well as additional size increases to follow. Also we expect for some types of uses, lightning will be available later this year.

这个计划是为了使新用户能够更快、更安全的体验比特币的强大功能而对比特币进行扩展。这种拓展包括了网络带宽、网络延迟、终端处理器和内存等多种东西。比特币的0.12版本包含了比现在快7被的签名认证，将允许更大的块和与规模相关的其他性能改进。比特币的开发者们在几个月中一直在努力，其努力的第一个就是隔离见证。在隔离见证之后的是多个额外的规模改进，包括Schnorr签名，这可以大大的压缩交易的大小以在相同的空间内获得更多的交易，同时尺寸也在同步增加。我们同时也在期待其他的一些应用，比如lightning将在今年晚些时候可以使用。

下个月区块满了该怎么办？共识签署那么多哪一个是真的？为什么不先增加core的区块大小？

I think everyone committed to the future of Bitcoin will collaborate to see it succeed, we could see this at the HK workshop – everyone wants to scale and improve Bitcoin. I think our best way to scale and improve Bitcoin quickly and safely is to collaborate, for all miners, exchanges, users and ecosystem companies to work together. The questions are only about which technical way is best.

There were 80,000 lines of code written in the bitcoin 0.12 release, however this code was written by dozens developers from different countries, companies and individuals. Blockstream is a one part of this only and the code is part of the Bitcoin project. Bitcoin developers who work for Blockstream have employment contracts guaranteeing their independence for their work on Bitcoin, because Blockstream understands that it is important for no company to control Bitcoin (including Blockstream).

The 0.12 release brings many needed performance improvements that allow Bitcoin to scale to more transactions per hour, and bigger blocks. The segregated witness feature increases the effective block-size once users upgrade.

我认为每个人都致力于比特币的未来，希望通过合作看到它的成功，我们在香港的圆桌会议中看到了这一点——每个人都想扩容和改进比特币。我们认为扩容和改善比特币快速和的办法就是进行合作，为所有矿工、交易所、生态系统用户和公司一起协作。问题是哪个技术方法是最好的。

在0.12版本中有大概80000行代码，但是这些代码是由几十个在不同国家、公司和部分个人开发者一起完成的。Blockstream只是其中的一部分，而这些代码也是比特币的一部分。为Blockstream工作的比特币开发者有一份特殊的合同来保障其自身的利益，因为我们不希望任何企业能够控制比特币（包括Blockstream）。

0.12版本的更新提供了很多必须的性能提升，它给比特币带来了更大的区块，并且在每小时内可以提供更多的交易。而一旦用户升级，隔离见证将能有效的增加区块的大小。

Blockstream公司和核心开发者之间是什么样的一种关系。Blockstream公司是向核心开发者付钱的吗，Blockstream公司是控制着比特币核心开发者吗？

There are over 50 active Bitcoin developers from countries all over the world, some of whom work for the many Bitcoin companies, and some of whom are independent. Some Bitcoin developers work for Blockstream, however Blockstream truly is not and does not want to be in charge of Bitcoin. Bitcoin developers who work for Blockstream have employment contracts guaranteeing their independence for their work on Bitcoin, because Blockstream understands that it is important for no company to control Bitcoin (including Blockstream).

全世界有50多个活跃的比特币开发者，他们中有人为比特币公司工作，有些人是独立个体。有的比特币核心开发者为Blockstream工作，然而Blockstream实际上并不想干涉比特币。Blockstream的这些比特币核心开发者和公司有签署协议，保证自己在于比特币事物上的独立性，因为Blockstream明白比特币公司（包括他们自己）在不能掌控比特币上有多重要。

Samson Mow在tweeter上讽刺挖苦Gavin，最近连Coinbase的CEO不得不拉黑你的账号。请问，作为BTCC的COO，李启元支持你这么做吗？

People in the Bitcoin ecosystem have a responsibility to be fair, balanced and honest in their comments. Confidence in the ecosystem can be weakened by unnecessarily dramatic statements that could be misleading, particularly when made by those perceived to be influential. While Bitcoin is decentralised, it is still important for people to act prudently. Samson’s tweets were often humorous in a way intended to remind people of their responsibility.

在比特币生态系统的人们有责任公平、公正和诚实的评论。信心在生态系统可以通过不必要的戏剧性声明所可能产生误导作用而削弱，特别是那些被认为是有影响力的人。当比特币是分散的，对大家来说慎重行事仍然很重要。Samson的tweets经常以一种幽默的方式来提醒大家他们的责任。

Classic缺点在哪里？

I think collectively we can more safely and quickly upgrade Bitcoin by working together. Bitcoin changes are normally made via the long standing open development process which reaches agreement on features by consensus amongst developers and the ecosystem of miners, exchanges, users and companies through widespread agreement. Many version upgrades have been safely made with excellent results during the last 5 years using this process. It is only with XT and now Classic that someone tried to bypass the collaborative upgrade process. Classic is a copy of Bitcoin with some rushed and incompatible changes. The main problem is not the features, but that Classic was not done in a spirit of collaboration, and so creates an “us” vs “them” mindset which makes it harder for people to agree on an outcome – this then creates unwanted drama, negative news and loss of confidence in Bitcoin’s future. We can easily achieve consensus if we gather requirements, make and review proposals and work together.

我认为通过大家共同的努力，我们可以安全和快速的升级比特币。比特币的变更通常是一个长期的、开放的过程。一些功能的达成将基于矿工、开发者、交易所、用户及企业的广泛认同。通过这个过程，在过去5年内很多版本的变更都非常的完美和安全。只有XT和现在的Classic试图绕过协同升级的过程。而Classic只是一个有一些不兼容和冲突变更的比特币的副本。关键并不是这些新的功能和特点，而是Classic并没有表现出任何合作精神，因此而滋长了”我们”和”他们”的对立的心态。这让大家更难去达成一致的结果，这也将导致很多不应该的戏剧性事件、负面新闻并且使得大家对比特币的未来失去信心。如果我们收集需求、共同制定和审查这些提案，我们将很容易的达成共识。

隔離見證涉及幾千行代碼量，更涉及到BTC底層結構的改動。目前沒有足夠長時間的驗證，你是怎麼得到的結論“隔离见证相对于硬分叉更快更安全”那？

The reason it is safer to do Segregated Witness first is because there is no chance for the network to split with a soft-fork like SW, while there are additional risks of network split with hard-forks, if they are not planned carefully and with reasonable time for everyone to upgrade. Soft-forks have been done many times and are safe because miners protect people during the upgrade process. In a hard-fork everyone must upgrade before it can be activated. It is common in other non-Bitcoin protocol network upgrades for there to be a period of backwards compatibility. Hard-forks are not backwards compatible so they take longer.

Bitcoin has had many upgrades with more lines of code than Segregated Witness and deployed multiple complex features. For comparison, the most recent release of Bitcoin, 0.12 Bitcoin has 80,000 lines of new code in it, and no one is saying it is not safe to run. The Bitcoin development team has lots of experience over 5 years of making improvements to Bitcoin. Segregated Witness has undergone extensive testing, and people who have looked at the code say that while the idea is innovative, the change is relatively simple and elegant and not that complicated to code. In hindsight it is the way that transactions should have been formatted from the beginning.

之所以先做隔离见证会更安全是因为网络不会像SW那样有机会进行软分叉，然而如果不能仔细规划，并给每个人合理时间进行升级的话，它将为网络硬分叉增加额外的的风险。软分叉已经出现过多次，但是因为矿工会在升级进程中保护所有人，所以它是安全的。在硬分叉的情况下，所有人都需要在其启动前进行升级。这种情况在其它非比特币协议网络升级中很普遍，因为向下兼容还需一段时间。硬分叉不属于向下兼容，所以需要的是将更长。

比特币的升级在编码行数上多于隔离见证，并且部署了许多复杂的特性。例如，最新发布的比特币0.12有八万多行的新编码，并且运行下来并没有人说它不安全。比特币开发团队有着五年多的经验，并对比特币不断进行改进。隔离见证并未进行广泛的测试，并且看过它代码的人说尽管其观点新颖，然而其改变相对普通、简洁且编程起来并不复杂。它的后见之明是交易在最初就应该统一规范。

你有什么证据证明区块大小每秒大于4 MB会导致垃圾邮件等安全问题？

There are several factors that determine the largest supportable block-size including bandwidth of miners, latency of the network, CPU overhead to validate transactions and the network protocol used to transfer the block. Testing and simulation has been done by a range of people concluding that 4 MB blocks are safe but much larger blocks start to have problems. One result was by academics http://fc16.ifca.ai/bitcoin/papers/CDE+16.pdf from 5 leading international universities.

有很多条件决定了最大可支持的区块大小，包括矿工的带宽、网络延时、验证交易的内存占用率和用于传送区块的网络协议。许多人通过测试和模拟得出结论，4MB大的区块是安全的，但是再大的就会出现问题。其可能出现的结果经来自世界上五所知名大学学者论证，请参阅http://fc16.ifca.ai/bitcoin/papers/CDE+16.pdf

什么是闪电网络，它能让比特币交易更快速吗？

Lightning is a layer2 mechanism to greatly increase Bitcoin scale by more efficient network usage, estimates range from 1,000x to 10,000 higher scale. Each lightning transaction is a real Bitcoin transaction that is sent to the recipient directly, rather than being broadcast to the Bitcoin network. This is achieved via a more advanced version of payment channels using smart-contracts and uses the transaction malleability fix from segregated witness. Lightning also makes Bitcoin transactions provide instant secure confirmation, whereas Bitcoin direct transactions take 10 minutes or more to confirm.

闪电网络是一种高效的网络使用机制，可以大量的增加比特币的规模。估计可以增加1000~10000倍的规模。每一个闪电交易都是一个直接发送给接收者的真实存在的比特币交易，而不是像以前那样广播到整个比特币网络中。这是通过使用一个更高级版本的支付渠道来实现的——隔离见证确定的可塑性交易及智能合约。闪电网络也同时可以让比特币交易提供一个即时的安全确认，而比特币的直接交易需要10分钟的等待或更多的确认数。

I have just one question here. As we all know, the transaction volume of bitcoin has been increasing dramatically in recent years. And the block size is reaching the limit of 1M. Several companies will have to postpone their’s development on bitcoin. At the current situation, you guys still refuse to increase the block size quickly. Why do you guys make such a choice besides the safety concerns you guys have been talking about?

The Bitcoin core developers are happy to collaborate with all developers. The core development team is very large, from many countries, companies and individuals. Over 50 active developers, and many more infrequent developers.

The core developers spent many months working on scaling features in Bitcoin 0.12 this year and last year. Bitcoin 0.12 which took about 8-months of work includes 80,000 lines of new code and scaling features including 7x faster signature validation, much faster block assembly. These features are needed to increase block-size. If not for this work increasing the block-size would not have been possible.

Bitcoin core evaluated two different methods to increase the block-size: via segregated witness soft-fork and via hard-fork. The soft-fork method is safer and faster because during a soft-fork upgrade miners protect users that have not yet upgraded. With hard-forks everyone has to upgrade before activation, which is slower.

The scale provided by segregated witness is essentially the same once users upgrade as a hard-fork. In addition segregated witness allows a new, cleverer type of scale with upgrade to Schnorr signatures that can reduce transaction sizes by up to 50% (in theory even up to 60% smaller) so we should ultimately be able to get up to 2x as many transactions from the same block-size.

With these features, it will be better to start expressing scale in terms of transactions per hour rather than block-size because as technology improves we can get more transactions per block. This is especially true for later layer2 mechanisms like lightning.

比特币核心开发者都很高兴与其他所有的开发人员合作。核心团队很大，来自于很多的国家和公司，还有个人开发者。有超过50的活跃开发者和更多的不活跃开发者。
在去年和今年，核心开发者用了好几个月的时间为比特币0.12版本的可扩展性功能而努力。0.12版本的比特币用了8个月的工作时间，包括80000多行新的代码和可扩展性功能（包括7倍速的签名验证，极大的增加了交易打包成块的速度）。这些功能对于增加区块大小是必须的。增加区块大小如果不是为了这些功能，则会是安全没有必要的。
比特币核心评估了两种增加区块大小的方法：通过隔离见证软分叉和通过硬分叉。软分叉方式是更加安全和快捷的，因为在软分叉的升级过程中，矿工可以保护全网中还未升级的用户。而在硬分叉中，所有人都要在分叉激活之前升级，这会更加的缓慢。
隔离见证提供的扩容本质上来说与用户一次性升级到硬分叉是相同的。此外，隔离见证允许一个新的、更智能的扩容——升级至Schnorr签名可以减少50%的交易大小（理论上可以减少60%）。所以我们最终应该能够在相同的区块大小内增加多一倍的交易数量。
有了这些功能，它将更好地在每小时的交易期限内扩容而不是区块大小，因为随着技术的提高我们可以在一个区块中包含更多的交易。这些都是真实的，比如类似闪电网络之类的第二层机制。

你对于比特币的未来有什么看法，社区的能力聚在一起如何改进？

I think the future of Bitcoin is very bright. Bitcoin offers attractive properties for users. During the next 12 – 18months many exciting new innovations should become available. Initial scale upgrades in the short term, and then high scale from lightning. We should also expect improved extensibility and features for Bitcoin from side-chains allowing innovative extensions like elements sidechain and liquid sidechain from blockstream, and from other companies and developers innovations like rootstock (ethereum contracts in Bitcoin), hivemind (prediction markets) and other new ideas like zerocash, snarks and experimental ideas.

我认为比特币前途光明，它能为用户提供很多引人注目的特性，许多新创新在接下来的12到18个月内会成为可能。短期内进行初始扩容，然后是闪电网的大范围扩容。我们还应期待延展性的提升，还有比特币侧链的特性：它允许创新延展性，比如Blockstream的elements侧链和Liquid侧链。还有来自其他公司或开发者的创新，比如像rootstock（比特币的以太坊合约）、hivemind（可预测市场）以及其他的如zerocash、snarks和experimental ideas这样的新观点。

在侧链上能更好的解决交易速度，那侧链上建议的是比特币吗？还是Q币于人民币？

Sidechains are more about extensibility than scale or speed, but the fees on a pegged sidechain are in BTC like with Bitcoin, so transactions on sidechains are a new source of fee revenue for miners, who secure sidechain transactions via merge-mining. Sidechains support extended functionality including issued assets such as CNY by issuers like QQ, or gold ETF or shares and bonds. Interestingly with smart-contracts you can even make options where the option contract is executed by the block-chain without having to trust an underwriting company.

侧链是相对于规模和速度更加具有扩展性的概念，但是同时在侧链上的费用也是使用BTC进行结算的，所以侧链上的交易将会是矿工新的收入来源，并且合并挖矿会让侧链更加安全。侧链的扩展功能包括类似于Q币之于人民币，又可能是类似黄金ETF、股票和债券的功能。有趣的是，使用智能合约，你甚至可以选择是通过区块链执行还是第三方担保公司来执行这笔合约。

翻译：BTCC