Pi Network白皮书
(中文翻译对照）
Introduction
引言
Problem: Accessibility of 1st Gen Cryptocurrencies问题:第一代加密货币的易用性
Solution: Pi - Mining Goes Mobile解决方案:Pi-让挖矿运行于移动终端
Pi Economic Model: Balancing Scarcity and AccessPi经济模型:稀缺性与获取性的平衡
Utility: Monetizing untapped resources in p2p效用:将p2p中尚未开发的资源货币化
Governance - Currency for and by the people治理——众创和众用的货币
Roadmap / Deployment plan路线图/部署计划
Draft 1 on March 14, 2019草案1 2019年3月14日
Preface
前言As the world becomes increasingly digital, cryptocurrency is a next natural step in the evolution of money. Pi is the first digital currency for everyday people, representing a major step forward in the adoption of cryptocurrency worldwide.随着世界变得越来越数字化，加密货币成为货币发展的自然趋势。Pi将是每一个人日常生活中使用的第一种数字货币，标志着全世界在采用加密货币方面向前迈进了一大步。
Our Mission: Build a cryptocurrency and smart contracts platform secured and operated by everyday people.我们的使命：建立一个平常人能运用的加密货币智能合约平台，既安全又易于操作。
Our Vision: Build the world's most inclusive peer-to-peer marketplace, fueled by Pi, the world's most widely used cryptocurrency.我们的愿景:在Pi(世界上使用最广泛的加密货币)的推动下，建立世界上最具包容性的p2p市场。
DISCLAIMER for more advanced readers: Because Pi's mission is to be inclusive as possible, we're going to take this opportunity to introduce our blockchain newbies to the rabbit hole 免责声明:因为Pi的使命是尽可能包容，我们将借此机会介绍给新入场的区块链新手们:)
Introduction: Why cryptocurrencies matter引言:为什么加密货币如此重要Currently, our everyday financial transactions rely upon a trusted third party to maintain a record of transactions. For example, when you do a bank transaction, the banking system keeps a record & guarantees that the transaction is safe & reliable. Likewise, when Cindy transfers $5 to Steve using PayPal, PayPal maintains a central record of $5 dollars debited from Cindy's account and $5 credited to Steve's. Intermediaries like banks, PayPal, and other members of the current economic system play an important role in regulating the world's financial transactions.目前，我们日常的金融交易依赖于一个值得信赖的第三方来维护交易记录。例如，当你进行银行交易时，银行系统会记录并保证交易是安全可靠的。同样，当辛迪使用贝宝向史蒂夫转移5美元时，贝宝保持着从辛迪账户借记5美元和记入史蒂夫账户5美元的中央记录。像银行、贝宝和当前经济体系的其他成员这样的中介机构在监管世界金融交易方面发挥着重要作用。
However, the role of these trusted intermediaries also has limitations:然而，这些值得信赖的中介机构的作用也有局限性:
- Unfair value capture. These intermediaries amass billions of dollars in wealth creation (PayPal market cap is ~$130B), but pass virtually nothing onto their customers - the everyday people on the ground, whose money drives a meaningful proportion of the global economy. More and more people are falling behind.1.不公平的价值获取。这些中介机构积累了数十亿美元的财富创造(贝宝的市值约为1300亿美元)，但几乎没有把任何东西转嫁给他们的客户——实地的普通人，他们攫取的钱财在全球经济中占有相当大的比重。越来越多的人被远远摔在身后而望尘莫及。
- Fees. Banks and companies charge large fees for facilitating transactions. These fees often disproportionately impact lower-income populations who have the fewest alternatives.2.费用。银行和公司为方便交易收取高额费用。这些费用往往严重影响到低收入人口，而他们别无选择。
- Censorship. If a particular trusted intermediary decides that you should not be able to move your money, it can place restrictions on the movement of your money.3.审查制度。如果一个信托机构认为你不应该转移你的钱，它可以对你的钱的流动设置限制。
- Permissioned. The trusted intermediary serves as a gatekeeper who can arbitrarily prevent anybody from being part of the network.4.许可。作为中间商的授信机构成为你进入全球网的守关人，可以任意阻止任何人成为网络的一份子。
- Pseudonymous. At a time when the issue of privacy is gaining greater urgency, these powerful gatekeepers can accidentally disclose – or force you to disclose – more financial information about yourself than you may want.5.隐私。在隐私问题变得越来越紧迫的时候，这些强大的看门人可能会意外地披露----或者强迫你披露----比你想要的更多的关于你自己的财务信息。
Bitcoin's "peer-to-peer electronic cash system," launched in 2009 by an anonymous programmer (or group) Satoshi Nakamoto, was a watershed moment for the freedom of money. For the first time in history, people could securely exchange value, without requiring a third party or trusted intermediary. Paying in Bitcoin meant that people like Steve and Cindy could pay each other directly, bypassing institutional fees, obstructions and intrusions. Bitcoin was truly a currency without boundaries, powering and connecting a new global economy.比特币的"点对点电子现金系统"于2009年由一个匿名的程序员(或团体)中本聪发起，是货币自由的一个分水岭。有史以来第一次，人们可以安全地交换价值，而不需要第三方或信任的中间人。用比特币支付意味着像史蒂夫和辛迪这样的人可以直接互相支付，绕过机构收费、障碍和入侵。比特币是一种真正的无国界货币，为新的全球经济提供动力和连接。Introduction to Distributed Ledgers分布式分类账介绍Bitcoin achieved this historical feat by using a distributed record. While the current financial system relies on the traditional central record of truth, the Bitcoin record is maintained by a distributed community of "validators," who access and update this public ledger. Imagine the Bitcoin protocol as a globally shared "Google Sheet" that contains a record of transactions, validated and maintained by this distributed community.比特币通过使用分布式记录实现了这一历史壮举。尽管目前的金融体系依赖于传统的真实记录，但比特币的记录是由一个分布式的"验证者"社区维护的，这些"验证者"负责访问和更新这个公共账簿。把比特币协议想象成一个全球共享的"谷歌表"，其中包含交易记录，由这个分布式社区验证和维护。
The breakthrough of Bitcoin (and general blockchain technology) is that, even though the record is maintained by a community, the technology enables them to always reach consensus on truthful transactions, insuring that cheaters cannot record false transactions or overtake the system. This technological advancement allows for the removal of the centralized intermediary, without compromising transactional financial security.比特币(以及一般的区块链技术)的突破在于，尽管记录是由社区维护的，但该技术使他们总是能够就真实交易达成共识，确保骗子不会记录虚假交易或超越系统。这种技术进步允许取消集中的中介，而不损害交易性金融安全。
Benefits of distributed ledgers分布式分类账的好处In addition to decentralization, bitcoin, or cryptocurrencies in general, share a few nice properties that make money smarter and safer, although different cryptocurrencies may be stronger in some properties and weaker in others, based on different implementations of their protocols. Cryptocurrencies are held in cryptographic wallets identified by a publicly accessible address, and is secured by a very strong privately held password, called the private key. This private key cryptographically signs transaction and is virtually impossible to create fraudulent signatures. This provides security and unseizability. Unlike traditional bank accounts that can be seized by government authorities, the cryptocurrency in your wallet can never be taken away by anyone without your private key. Cryptocurrencies are censorship resistant due to the decentralized nature because anyone can submit transactions to any computer in the network to get recorded and validated. Cryptocurrency transactions are immutable because each block of transactions represents a cryptographic proof (a hash) of all the previous blocks that existed before that. Once someone sends you money, they cannot steal back their payment to you (i.e., no bouncing checks in blockchain). Some of the cryptocurrencies can even support atomic transactions. "Smart contracts" built atop these cryptocurrencies do not merely rely on law for enforcement, but directly enforced through publicly auditable code, which make them trustless and can potentially get rid of middlemen in many businesses, e.g. Escrow for real estate.除了地方分权，比特币，或者一般的加密货币，共享一些好的属性，使货币更加智能和安全，虽然不同的加密货币可能在某些属性上更强，而在其他的弱，基于他们的协议的不同实现。加密货币存放在由公共可访问地址标识的加密钱包中，并由一个非常强大的私人密码保护，称为私人密钥。这种私钥通过密码签署交易，实际上不可能创建欺诈性签名。这提供了安全性和无可可抓取性。不像传统的银行账户可以被政府当局查封，你钱包里的加密货币永远不会被没有你私人钥匙的任何人拿走。由于分散的特性，加密货币具有抗审查的能力，因为任何人都可以向网络中的任何一台计算机提交交易，以获得记录和验证。加密货币事务是不可变的，因为每个事务块表示之前存在的所有块的加密证明(散列)。一旦有人寄钱给你，他们不能偷回他们的付款给你(也就是说，没有跳票在块环链)。一些加密货币甚至可以支持原子交易。建立在这些加密货币之上的"智能合同"不仅依赖于执法，而且直接通过可公开审计的代码执行，这使得它们不受信任，并有可能摆脱许多企业的中间商，例如房地产托管中介。
Securing distributed ledgers (Mining)分布式总账的安全(挖矿)One of challenges of maintaining a distributed record of transactions is security – specifically, how to have an open and editable ledger while preventing fraudulent activity. To address this challenge, Bitcoin introduced a novel process called Mining (using the consensus algorithm "Proof of Work") to determine who is "trusted" to make updates to the shared record of transactions.维护分布式交易记录的挑战之一是安全性——具体来说，如何在防止欺诈活动的同时拥有一个开放和可编辑的分类账。为了应对这一挑战，比特币引入了一种名为挖矿(使用共识算法"工作证明")的新颖过程，以确定谁是"可信任的"，从而更新交易的共享记录。
You can think of mining as a type of economic game that forces "Validators" to prove their merit when trying to add transactions to the record. To qualify, Validators must solve a series of complex computational puzzles. The Validator who solves the puzzle first is rewarded by being allowed to post the latest block of transactions. Posting the latest block of transactions allows Validators to "mine" a Block Reward - currently 12.5 bitcoin (or ~$40,000 at the time of writing).你可以认为挖矿是一种经济游戏，它迫使"验证者"在试图将交易添加到记录中时证明自己的价值。为了验证，验证器必须解决一系列复杂的计算难题。首先解决这个难题的贡献者将获得允许发布最新的交易块的奖励。发布最新的交易块允许验证器"挖掘"一块奖励-目前12.5比特币(约合40,000美元在本文撰写时)。
This process is very secure, but it demands enormous computing power and energy consumption as users essentially "burn money" to solve the computational puzzle that earns them more Bitcoin. The burn-to-reward ratio is so punitive that it is always in Validators' self-interest to post honest transactions to the Bitcoin record.这个过程非常安全，但它需要巨大的计算能力和能源消耗，因为用户实际上是"烧钱"来解决计算难题，从而赚取更多的比特币。烧钱与奖励的比例是如此的惩罚性，以至于在比特币记录上公布诚实的交易始终符合验证者的自身利益。
Problem: Centralization of power and money put 1st Generation Cryptocurrencies out of reach.问题:权力和金钱的集中使第一代加密货币无法触及。In the early days of Bitcoin, when only a few people were working to validate transactions and mining the first blocks, anyone could earn 50 BTC by simply running Bitcoin mining software on their personal computer. As the currency began to gain in popularity, clever miners realized that they could earn more if they had more than one computer working to mine.在比特币的早期，只有少数人在验证交易和挖掘第一个块，任何人只要在个人电脑上运行比特币挖掘软件就可以赚到50比特币。随着比特币开始流行，聪明的矿工们意识到，如果他们有不止一台电脑来开采，他们可以赚得更多。
As Bitcoin continued to increase in value, entire companies began to spring up to mine. These companies developed specialized chips ("ASICs") and constructed huge farms of servers using these ASIC chips to mine Bitcoin. The emergence of these enormous mining corporations, known drove the Bitcoin Gold Rush, making it very difficult for everyday people to contribute to the network and get rewarded. Their efforts also began consuming increasingly large amounts of computing energy, contributing to mounting environmental issues around the world.随着比特币价值的持续增长，大批公司开始筹建矿场。这些公司开发了专门的芯片("ASIC")，并利用这些ASIC芯片构建了巨大的服务器群来开采比特币。这些庞大的矿业公司的出现，推动了比特币淘金热，使得普通人很难为网络做出贡献并获得回报。他们的努力也开始消耗越来越大量的计算能源，导致全球环境问题日益严重。
The ease of mining Bitcoin and the subsequent rise of Bitcoin mining farms quickly produced a massive centralization of production power and wealth in Bitcoin's network. To provide some context, 87% of all Bitcoins are now owned by 1% of their network, many of these coins were mined virtually free in their early days. As another example, Bitmain, one of Bitcoin's biggest mining operations has earned billions in revenue and profits.挖掘比特币的便捷以及随之而来的比特币矿场的兴起，迅速促成了比特币网络生产力和财富的大规模集中。为了提供一些背景信息，87%的比特币现在被1%的比特币网络所拥有，其中许多比特币在早期几乎是免费开采的。另一个例子是Bitmain，比特币最大的采矿业务之一，已经获得了数十亿美元的收入和利润。
The centralization of power in Bitcoin's network makes it very difficult and expensive for the average person. If you want to acquire Bitcoin, your easiest options are to:比特币网络中的权力集中对普通人来说是非常困难和昂贵的。如果你想获得比特币，你最简单的选择是:
- Mine It Yourself. Just hook up the specialized hardware (here's a rig on Amazon, if you're interested!) and go to town. Just know that since you'll be competing against massive server farms from across the world, consuming as much energy as the country of Switzerland, you won't be able to mine much.1.自己挖掘。只要拥有专门的硬件(如果你感兴趣的话，这里是亚马逊上的一个平台!)然后去淘换。只要知道，由于你将与来自世界各地的大型服务器农场竞争，消耗的能源相当于整个瑞士国家的能源，而你却将无法开采太多的资源。
- Buy Bitcoin on an exchange. Today, you can buy Bitcoin at a unit price of $3,500 / coin at the time of writing (note: you can buy fractional amount of Bitcoin!) Of course, you would also be taking on substantial risk in doing so as the price of Bitcoin is quite volatile.2.在交易所购买比特币。如今，在撰写本文时，你可以以每枚3500美元的单位价格购买比特币(注意:你可以购买部分数量的比特币!)当然，由于比特币的价格相当不稳定，这样做也将承担巨大的风险。
Bitcoin was the first to show how cryptocurrency could disrupt the current financial model, giving people the ability to make transactions without having a third party in the way. The increase in freedom, flexibility, and privacy continues to drive the inevitable march toward digital currencies as a new norm. Despite its benefits, Bitcoin's (likely unintended) concentration of money and power present a meaningful barrier to mainstream adoption. As Pi's core team has conducted research to try to understand why people are reluctant to enter the cryptocurrency space. People consistently cited the risk of investing/mining as a key barrier to entry.比特币首次展示了加密货币如何打破当前的金融模式，使人们能够在没有第三方阻碍的情况下进行交易。自由度、灵活性和隐私的增加继续推动着数字货币不可避免地成为一种新的规范。尽管比特币有很多好处，但它(可能是无意中)的资金和权力集中给主流应用带来了很大的障碍。Pi的核心团队进行了一项研究，试图理解为什么人们不愿意进入加密货币领域。人们一直认为投资/采矿的风险是进入市场的一个关键障碍。
Solution: Pi - Enabling mining on mobile phones解决方案:在移动电话上实现Pi挖掘After identifying these key barriers to adoption, the Pi Core Team set out to find a way that would allow everyday people to mine (or earn cryptocurrency rewards for validating transactions on a distributed record of transactions). As a refresher, one of the major challenges that arises with maintaining a distributed record of transactions is ensuring that updates to this open record are not fraudulent. While Bitcoin's process for updating its record is proven (burning energy / money to prove trustworthiness), it is not very user (or planet!) friendly. For Pi, we introduced the additional design requirement of employing a consensus algorithm that would also be extremely user friendly and ideally enable mining on personal computers and mobile phones.在确定了这些采用的关键障碍之后，Pi核心小组开始寻找一种方法，让普通人能够挖掘(或者通过验证分布式交易记录的交易获得加密货币奖励)。作为一个守护者，维护分布式事务记录的主要挑战之一是确保对这个公开记录的更新不是欺诈。虽然比特币更新记录的过程已经得到证实(燃烧能量/金钱来证明可信度)，但它并不是很好的用户(或星球!)友好的。对于Pi，我们引入了额外的设计要求，即采用一致性算法，这种算法对用户非常友好，理想情况下可以在个人电脑和移动电话上进行挖掘。
In comparing existing consensus algorithms (the process that records transactions into a distributed ledger), the Stellar Consensus Protocol emerges as the leading candidate to enable user-friendly, mobile-first mining. Stellar Consensus Protocol (SCP) was architected by David Mazières a professor of Computer Science at Stanford who also serves as Chief Scientist at the Stellar Development Foundation. SCP uses a novel mechanism called Federated Byzantine Agreements to ensure that updates to a distributed ledger are accurate and trustworthy. SCP is also deployed in practice through the Stellar blockchain that has been operating since 2015.在比较现有的一致性算法(将事务记录到分布式分类账的过程)时，Stellar一致性协议成为支持用户友好、移动优先挖掘的主要候选方案。恒星共识协议(starConsensusProtocol，SCP)是由斯坦福大学计算机科学教授Davidmazi设计的，他同时也是恒星发展基金会的首席科学家。Scp使用一种称为联邦拜占庭协议(federatedbyzantineagreement)的新机制来确保分布式分类账的更新是准确和可信的。Scp也通过自2015年以来一直运行的Stellar区块链在实践中进行部署。
A simplified introduction to consensus algorithms一致性算法简介Before jumping to introducing the Pi consensus algorithm, it helps to have a simple explanation on what a consensus algorithm does for a blockchain and the types of consensus algorithms that today's blockchain protocols generally use, e.g. Bitcoin and SCP. This section is explicitly written in a oversimplified manner for the sake of clarity, and is not complete. For higher accuracy, see the section Adaptations to SCP below and read the stellar consensus protocol paper.在介绍Pi一致性算法之前，先简单解释一下一致性算法对区块链的作用，以及当今区块链协议通常使用的一致性算法的类型，例如比特币和SCP。为了清晰起见，本节显式地以过于简化的方式编写，并且不完整陈述。要获得更高的准确性，请参阅下面的SCP适应章节，并阅读主要共识协议文件。
A blockchain is a fault-tolerant distributed system that aims to totally order a list of blocks of transactions. Fault-tolerant distributed systems is an area of computer science that has been studied for many decades. They are called distributed systems because they do not have a centralized server but instead they are composed of a decentralized list of computers (called nodes or peers) that need to come to a consensus as to what is the content and total ordering of blocks. They are also called fault-tolerant because they can tolerate a certain degree of faulty nodes into the system (e.g. up to 33% of nodes can be faulty and the overall system continues to operate normally).区块链是一个容错的分布式系统，旨在完全有序的事务块列表。容错分布式系统是计算机科学的一个领域，已经研究了几十年。它们之所以被称为分布式系统，是因为它们没有一个集中的服务器，而是由一个分散的计算机列表(称为节点或对等点)组成，这些计算机需要就块的内容和总次序达成共识。它们也被称为容错节点，因为它们可以容忍系统中某种程度的错误节点(例如，多达33%的节点可能出错，整个系统继续正常运行)。
There are two broad categories of consensus algorithms: The ones that elect a node as the leader who produces the next block, and the ones where there is no explicit leader but all nodes come to a consensus of what the next block is after exchanging votes by sending computer messages to each other. (Strictly speaking the last sentence contains multiple inaccuracies, but it helps us explain the broad strokes.)一致同意算法有两大类:一类是选出一个节点作为产生下一个块的领导者，另一类是没有明确的领导者，但所有节点通过互相发送计算机消息，对下一个块的内容达成一致意见。(严格来说，最后一句包含了多个不准确的地方，但是它帮助我们解释了大致内容。)
Bitcoin uses the first type of consensus algorithm: All bitcoin nodes are competing against each other in solving a cryptographic puzzle. Because the solution is found randomly, essentially the node that finds the solution first, by chance, is elected the leader of the round who produces the next block. This algorithm is called "Proof of work" and results in a lot of energy consumption.比特币使用第一种共识算法:所有比特币节点在解决密码难题时相互竞争。因为解是随机发现的，本质上，首先找到解的节点，偶然地，被选举为产生下一个块的轮的领导者。这种算法被称为"工作证明"，并导致大量的能源消耗。
A simplified introduction to Stellar Consensus Protocol《恒星共识议定书》简介Pi uses the other type of consensus algorithms and is based on the Stellar Consensus Protocol (SCP) and an algorithm called Federated Byzantine Agreement (FBA). Such algorithms don't have energy waste but they require exchanging many network messages in order for the nodes to come to "consensus" on what the next block should be. Each node can independently determine if a transaction is valid or not, e.g. authority of making the transition and double spending, based on the cryptographic signature and the transaction history. However, for a network of computers to agree on which transactions to record in a block and the order of these transactions and blocks, they need to message each other and have multiple rounds of voting to come to consensus. Intuitively, such messages from different computers in the network about which block is the next would look like the following: "I propose we all vote for block A to be next"; "I vote for block A to be the next block"; "I confirm that the majority of the nodes I trust also voted for block A", from which the consensus algorithm enables this node to conclude that "A is the next block; and there could be no block other than A as the next block"; Even though the above voting steps seem a lot, the internet is adequately fast and these messages are lightweight, thus such consensus algorithms are more lightweight than Bitcoin's proof of work. One major representative of such algorithms is called Byzantine Fault Tolerance (BFT). Several of the top blockchains today are based on variants of BFT, such as NEO and Ripple.Pi使用其他类型的一致性算法，并基于StellarConsensusProtocol(SCP)和一个名为FederatedByzantineAgreement(FBA)的算法。这种算法没有能源浪费，但是它们需要交换许多网络消息，以便节点对下一个块应该是什么达成"共识"。每个节点可以独立地确定一个事务是否有效，例如根据加密签名和事务历史确定进行转换和重复开销的权限。然而，对于一个计算机网络来说，要商定在一个块中记录哪些交易以及这些交易和块的顺序，它们需要彼此发送消息，并进行多轮投票才能达成共识。从直观上看，来自网络中不同计算机的关于下一个块是哪个块的信息看起来像这样:"我提议我们都投票支持a块成为下一个块";"我投票支持a块成为下一个块";"我确认我信任的大多数节点也投票支持a块"，从这个一致性算法中，该节点可以得出结论:"a是下一个块;除了a之外，没有其他块是下一个块";尽管上面的投票步骤看起来很多，但互联网足够快，这些信息是轻量级的，因此这种一致性算法不仅仅是工作的证明。这种算法的一个主要代表被称为拜占庭将军问题算法。今天的一些顶级块环链是基于BFT的变体，如NEO和Ripple。
One major criticism of BFT is that it has a centralization point: because voting is involved, the set of nodes participating in the voting "quorum" are centrally determined by the creator of the system in its beginning. The contribution of FBA is that, instead of having one centrally determined quorum, each node sets their own "quorum slices", which will in turn form different quorums. New nodes can join the network in a decentralized way: they declare the nodes that they trust and convince other nodes to trust them, but they don't have to convince any central authority.对BFT的一个主要批评是它有一个集中点:因为涉及到投票，参与投票"quorum"的节点集在开始时由系统的创建者集中决定。Fba的贡献在于，每个节点都设置了自己的"法定人数小组"，而不是由一个中央决定的法定人数，这些法定人数小组又会形成不同的四分之一。新的节点可以以分散的方式加入网络:它们声明它们信任的节点，并说服其他节点信任它们，但它们不需要说服任何中央权威机构。
SCP is one instantiation of FBA. Instead of burning energy like in Bitcoin's proof of work consensus algorithm, SCP nodes secure the shared record by vouching for other nodes in the network as trustworthy. Each node in the network builds a quorum slice, consisting of other nodes in the network that they deem to be trustworthy. Quorums are formed based on its members quorum slices, and a validator will only accept new transactions if and only if a proportion of nodes in their quorums will also accept the transaction. As validators across the network construct their quorums, these quorums help nodes to reach consensus about transactions with guarantee on security. You can learn more about the Stellar Consensus Protocol by watching this short, 7 min explanation video or checking out this technical summary of SCP.Scp是FBA的一个实例。不像比特币的工作证明一致性算法那样消耗能量，SCP节点通过担保网络中的其他节点是可信的来保护共享记录。网络中的每个节点构建quorumslice，quorumslice由网络中它们认为可信的其他节点组成。量程是根据其成员的法定人数小组形成的，并且只有当且仅当量程中的一部分节点也接受事务时，验证器才会接受新的事务。由于整个网络的验证器构造它们的准则，这些准则帮助节点在保证安全的前提下就事务达成共识。你可以通过观看这个7分钟的简短解释视频或者查看SCP的技术总结来了解更多关于恒星一致性协议的信息。
Pi's Adaptations to Stellar Consensus Protocol (SCP)Pi对恒星协商一致协议(SCP)的适应Pi's consensus algorithm builds atop SCP. SCP has been formally proven [Mazieres 2015] and is currently implemented within the Stellar Network. Unlike Stellar Network consisting mostly of companies and institutions (e.g., IBM) as nodes, Pi intends to allow devices of individuals to contribute on the protocol level and get rewarded, including mobile phones, laptops and computers. Below is an introduction on how Pi applies SCP to enabling mining by individuals.Pi的一致性算法建立在SCP之上。Scp已被正式证明[Mazieres2015]，目前正在恒星网络中实施。与主要由公司和机构(如IBM)组成的StellarNetwork不同，Pi打算允许个人设备在协议层面做出贡献并获得奖励，包括移动电话、笔记本电脑和计算机。下面介绍Pi如何将SCP应用到个人挖矿中。
There are four roles Pi users can play, as Pi miners. Namely:用户可以扮演四个角色，即:
• Pioneer. A user of the Pi mobile app who is simply confirming that they are not a "robot" on a daily basis. This user validates their presence every time they sign in to the app. They can also open the app to request transactions (e.g. make a payment in Pi to another Pioneer)• 先锋。Pi手机应用的用户每天只是简单地确认他们不是"机器人"。这个用户每次登录到应用程序时都会验证他们的存在。他们还可以打开应用程序请求交易(例如用Pi向另一个先行公司付款)
• Contributor. A user of the Pi mobile app who is contributing by providing a list of pioneers he or she knows and trusts. In aggregate, Pi contributors will build a global trust graph.• 贡献者。Pi手机应用程序的用户，通过提供他或她所认识和信任的先锋名单来做出贡献。总的来说，Pi贡献者将建立一个全局信任图。
• Ambassador. A user of the Pi mobile app who is introducing other users into Pi Network.• 大使。一个Pi手机应用程序的用户，他正在将其他用户引入Pi网络。
• Node. A user who is a pioneer, a contributor using the Pi mobile app, and is also running the Pi node software on their desktop or laptop computer. The Pi node software is the software that runs the core SCP algorithm, taking into account the trust graph information provided by the Contributors.• 节点。一个使用Pi移动应用程序的先锋，一个贡献者，并且在他们的台式机或笔记本电脑上运行Pi节点软件。Pi节点软件是运行核心SCP算法的软件，此软件参照贡献者提供的信任图信息。
A user can play more than one of the above roles. All roles are necessary, thus all roles are rewarded with newly minted Pi on a daily basis as long as they participated and contributed during that given day. In the loose definition of a "miner" being a user who receives newly minted currency as a reward for contributions, all four roles are considered to be Pi miners. We define"mining" more broadly than its traditional meaning equated to executing proof of work consensus algorithm as in Bitcoin or Ethereum.用户可以扮演上述多个角色。所有的角色都是必要的，因此所有的角色都会在每天的基础上获得新的Pi币，只要他们在那一天参与并做出贡献。在对"miner"的宽松定义中，"miner"是指获得新币作为贡献奖励的用户，所有四个角色都被认为是Pi矿工。我们对"挖矿"的定义比传统意义上的"执行工作证明一致性算法"更宽泛，比如在比特币或以太网中。
First of all, we need to emphasize that the Pi Node software has not been released yet. So this section is offered more as an architectural design and as a request to solicit comments from the technical community. This software will be fully open source and it will also heavily depend on stellar-core which is also open source software, available here. This means that anyone in the community will be able to read, comment and propose improvements on it. Below are the Pi proposed changes to SCP to enable mining by individual devices.首先，我们需要强调的是Pi Node软件还没有发布。因此，本节更多的是作为一个架构设计提供的，也是一个向技术社区征求意见的请求。这个软件将是完全开源的，它也将严重依赖恒星核心，这也是开源软件，可在这里。这意味着社区中的任何人都可以阅读、评论并提出改进建议。下面是Pi提议的SCP更改，以支持单设备挖掘。
Nodes节点For readability, we define as a correctly connected node to be what the SCP paper refers to as an intact node. Also, for readability, we define as the main Pi Network to be the set of all intact nodes in the Pi Network. The main task of each Node is to be configured to be correctly connected to the main Pi Network. Intuitively, a node being incorrectly connected to the main network is similar to a Bitcoin node not being connected to the main bitcoin network.为了便于阅读，我们将SCP文章中提到的正确连接节点定义为完整节点。另外，为了可读性，我们将主Pi网络定义为Pi网络中所有完整节点的集合。每个节点的主要任务是配置为正确连接到主Pi网络。直观地说，一个不正确地连接到主网络的节点类似于一个没有连接到主比特币网络的比特币节点。
In SCP's terms, for a node to get correctly connected means that this node must chose a "quorum slice" such that all resulting quorums that include this node intersect with the existing network's quorums. More precisely, a node vn+1 is correctly connected to a main network N of n already correctly connected nodes (v1, v2, …, vn) if the resulting system N' of n+1 nodes (v1, v2, …, vn+1) enjoys quorum intersection. In other words, N' enjoys quorum intersection iff any two of its quorums share a node. – i.e., for all quorums U1 and U2, U1∩U2 ≠ ∅.用SCP的术语来说，一个节点要正确连接意味着这个节点必须选择一个"量子组"，这样包含这个节点的所有产生的量子与现有网络的量子相交。更准确地说，一个节点vn+1正确连接到一个主网络n的n个已经正确连接的节点(v1，v2，…，vn)，如果得到的系统n'的n+1节点(v1，v2，…，vn+1)享有量子交集。换句话说，n'享有量子链接权，当且仅当其任意两个量子共享一个节点。–即，对于所有的量子集U1和U2，U1和U2交集≠任意值。
The main contribution of Pi over the existing Stellar consensus deployment is that it introduces the concept of a trust graph provided by the Pi Contributors as information that can be used by the Pi nodes when they are setting up their configurations to connect to the main Pi Network.对于现有的恒星共识部署，Pi的主要贡献是引入了Pi贡献者提供的信任图的概念，作为Pi节点在设置连接到主Pi网络的配置时可以使用的信息。
When picking their quorum slices, these Nodes must take into consideration the trust graph provided by the Contributors, including their own security circle. To assist in this decision, we intend to provide auxiliary graph analysis software to assist users running Nodes to make as informed decisions as possible. This software's daily output will include:在选择它们的待接入组时，这些节点必须考虑贡献者提供的信任图，包括它们自己的安全圈。为了协助这一决定，我们打算提供辅助图形分析软件，以帮助运行节点的用户做出尽可能知情的决定。该软件的日常输出包括:
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