卡尔达诺在权益证明上的研究代表了加密技术的重大进步。 乌洛波洛斯通过数学上的严谨的证明第一次为权益证明算法提供了安全的保障。 这对于旨在承载数十亿美元价值流通的加密币系统来说是极其重要的。另外，如果区块链想成为新金融系统的基础设施，它必须能够轻松处理数百万用户。权益证明的节能性，高效性的特点也为加密币系统的扩张提供了可能。乌洛波洛斯协议为卡尔达诺的一个重要组成部分，卡尔达诺是目前正在开发的第三代区块链系统。在这段视频中，Aggelos Kiayias教授对权益证明为我们作出深入的分析，他具体解释了相对工作证明， 权益证明的众多优势。
为了方便大家学习， 我们整理出视频的文字稿如下：
So the Ouroboros protocol is the core of the Cardano blockchain
所以乌洛波洛斯协议是卡尔达诺区块链的核心
It is the settlement layer, which basically means that users can ask the layer to see
它是个结算层 基本上代表着用户可以要求这结算层来确认
whether the transaction has been integrated and its output has been accepted by the network.
交易是否已经整合 它的结果是否已被网络接受
So, the settlement layer, is one of the most critical components to a cryptocurrency,
因此 结算层可以说是加密货币最重要的组成部分之一
it is possible to take a single server and implement the settlement layer as a centralized service.
是有可能可以采用单个服务器 并将结算层作为中心化服务的
While this works, it has a very significant disadvantage, it introduces a single point of failure in the system,
这固然有效 但它有一个非常显着的缺点 它在系统中带来了单点故障
so while this would provide liveness about transactions, as we say, transactions would be accepted in the system.
虽然这会提供交易的活跃性 但正如我们所说 交易可在系统中被接受
If the server is hacked, or if the server is controlled by someone who wants to censor transactions,
但如果服务器被黑客攻击 或者服务器被想要监察交易的人所控制
it will be completely at the mercy of those that control the system, of what transactions can be included or not.
它将完全受控制系统的人所支配 他可以选择包括或不包括任何交易
So this why decentralization is so important for cryptocurrencies,
所以这也就是为什么去中心化对加密货币如此重要，
so decentralizations able to distribute the trust from a single point of failure to a set of actors that distributively or collaboratively,
所以去中心化能将信任 从单点故障转化到一组分布或协作的参与者
will produce the same service of the settlement layer.
同时可提共与结算层相同的服务
This actually points to a classical problem in computer science that is known as consensus.
这也带来了计算机科学中的一个经典问题 即所谓的共识
Consensus in computer science have been studied for over 40 years,
计算机科学的共识已经被研究了40多年
and to introduce the problem the parties face when they want to reach a common agreement to produce the same output.
也就是当各方在达成共同协议以获得相同结果时 所需面临的问题。
While we have a very good understanding of the problem in literature about this problem,
虽然我们在文献中对于这个问题已经有了相当好的理解
almost all of the solutions that have been studied before the advent of the Bitcoin protocol shared the same deficiency.
但几乎所有在比特币出现前的解决方案都存在相同的缺陷
It assumed that the set of parties that are running the protocol are known,
它们假设运行协议的一群人为已知对象
basically there is a reliable naming infrastructure and the parties that are executing the protocol know each other.
基本上有一个可靠的知名基础设施 而执行协议的各方互相认识
While this made sense, for classical system in computer science
对于计算机科学中的经典系统来说 虽然这听起来有道理
it is not compatible with the way that the internet works.
但它与互联网的工作方式不兼容
There is no reliable name infrastructure that is globally available,
互联网并没有一个全球可用 可靠的知名基础设施，
so for the first time, with the bitcoin protocol, in 2009,
因此这也是第一次 随着2009年比特币协议的出现
it became feasible to think about solving consensus without assuming pre-existing names,
可以开始思考 如何在不假设预先知道名字的情况下
for the participants that are running the protocol,
来为执行协议的参与者解决共识问题
and this is very important, because it removes from the solution of the consensus problem,
这非常重要 因为它从共识问题的解决方案中跳脱出来
it removes any assumption about what are the participants that are running the protocol.
它推翻了有关运行协议的参与者的任何假设
The execution of the protocol becomes public and basically all interested parties,
协议的执行变得公开 基本上任何有兴趣的人
are open and free to become part of the protocol execution
都是开放和自由地可以成为协议执行的一部分
and contribute to the integrity of the ledger, in this way, the integrity of the system is maximized,
帮助分类账本的完整性 而这样 系统的完整性得到最大化
and it is feasible to provide a settlement that is extremely hard to be disrupted.
并且提供一个极难被破坏但可行的解决方案
Nevertheless, a significant deficiency of the bitcoin protocol is tremendous energy requirement,
然而，比特币协议有一个显着缺陷就是巨大的能源需求
the protocol, in order to operate, it requires for the participants, to solve what is know as Proof of Work.
为了运行此协议 它需要参与者 解决所谓的工作证明(PoW)
This means that each one of the servers that are participating and implementing this settlement layer,
这代表着每个参与并实施结算层的服务器
they have to solve a hard computational problem, that basically have to waste a lot of energy to prove to the other participants,
他们必须解决一个困难的计算问题 必须浪费大量的能源来向其他参与者证明
that their proposal for the next set of transactions to be processed, is the one that had to be included in the settlement layer.
他们对下一组要处理的交易的提案 会是必须被包含在结算层中
This, while it provides to the protocol many of its decentralization qualities that are very desirable,
这虽然为协议提供了许多非常理想的去中心化特性
it also comes with a downside, of requiring an extremely high energy expenditure.
它也带来了缺点 它需要极高的能源消耗
For that reason, it was early on discussed in the bitcoin community,
也因为这个原因 比特币社群很早就开始讨论
whether it is feasible to retain the decentralization qualities that are provided by the bitcoin blockchain
是否有办法可以保留比特币区块链提供的去中心化
and remove the energy waste that comes together with the protocol.
并同时去除协议附带的能源浪费
There are many ideas that were proposed by a number of people that are thinking about this problem,
很多人考虑了这个问题 也提出了许多想法，
but proof of stake became the one that was the most prominent, as the most convincing way,
但是最著名也最有说服力的方式就是权益证明(PoS)
of removing this need for proof of work, and the energy waste that comes with it from the bitcoin blockchain.
它去除了所需的工作证明 以及比特币区块链带来的能源浪费。
So while proof of work is the fundamental component of the bitcoin blockchain,
因此 虽然工作证明是比特币区块链的基本组件
by its very nature, it requires to spend energy in order to advance the protocol,
就其性质而言 它需要消耗能源来推进协议
now what happens in the proof of stake case is that what the participants of the protocol do
现在 在权益证明中发生的是 协议参与者所做的事情
is instead of actually spending energy to advance the protocol,
不再是实际消耗能源来推进协议
they refer to resources they have that already exists and are recorded in the ledger.
他们参考了已经拥有的资源 并将它记录在分类账本中
This referral, does not require the energy expenditure, that happens with proof of work.
而这个参考 将不再需要工作证明中的能源消耗
This is what enables proof of stake, to provide a similar type of decentralization as in the case of bitcoin
这使权益证明有能力提供了与比特币相似的去中心化
but without actually having the energy waste that comes with bitcoin or any other proof of work based protocol.
但实际上并没有比特币或任何其他工作证明协议附带的能源浪费
So proof of stake protocols that tries to take advantage of all the state-of-the-art cryptographic tools that are available right now,
因此 权益证明试图利用现在所有最先进的加密工具
to provide blockchain protocols that can actually scale and be more participatory,
提供区块链协议来得到更多的可扩展性和参与性
than any other protocols that are in the distributed ledger space.
比目前在分布式分类账本空间中的任何其他协议来得还要多
So because exactly proof of stake protocols are based on cryptographic tools, such as digital signatures, public certificates,
因为权益证明协议是基于加密工具 例如数字签名 公共凭证
it is feasible to use cryptographic protocols that provide all kinds of useful services
这也让利用加密协议来提供各种有用的服务成为可行的
and build these protocols on top of proof of stake ledgers in a very natural fashion.
并以非常自然的方式在权益证明分类账本上构建这些协议
So in this way, proof of stake ledger can provide a type of functionality, which is quite versatile,
因此 通过这种方式 权益证明分类账本可以提供一种通用的功能
that can meet many different applications, including electronic voting, supply chain management,
可以满足许多不同的应用 包括电子投票 供应链管理
and many others that could be of potentially high value for distributed ledger applications.
以及许多其他对分布式分类账本应用可能具有潜在高价值的东西
翻译： Mihori ，洪嘉隆
本视频摘要，请参见 摘要：什么是权益证明？