Bitcoin Whitepaper: a beginner's guide
Article Provided: Smart Blockchain Cloud Storage
灵动区块链
The Bitcoin whitepaper, Bitcoin: A Peer-to-Peer Electronic Cash System, was published in 2008 by Satoshi Nakamoto. Bitcoin is revolutionizing the global payments industry and people around the world are rethinking the meaning of their money. Moreover, the underlying technology and network that process Bitcoin transactions, known as blockchain, is transforming industries as varied as banking, farming, logistics, healthcare, elections and manufacturing, to name a few. All this is made possible by Satoshi Nakamoto's groundbreaking work published in 2008 which outlines what Bitcoin is and how it works, as presented in the original Bitcoin whitepaper.
Smart blockchaincloud storage recommendations first look at the guide
How To Use This Guide
Bitcoin.com offers a simplified explanation of Nakamoto's work. We provide annotations for all 12 sections of the whitepaper. Text in italics is used to provide commentary and annotations to distinguish the author's views from those of Satoshi Nakamoto's.
1. Introduction
Bitcoin creator, Satoshi Nakamoto discusses the web's reliance on trusted third parties such as banks and credit card companies to process electronic payments. The traditional method may work for most transactions but problems do occur when financial institutions facilitate the buying and selling of goods on the internet. Here are some of the weaknesses of traditional electronic payments involving third parties:
[if !supportLists]· [endif]Transactions can be reversed since banks must mediate disputes that inevitably arise.
Think of disputes that routinely take place between merchants, consumers and other parties, such as payment processors, PayPal or tax authorities.
[if !supportLists]· [endif]Banks' intervention (i.e., mediation) increases transaction costs and this also limits the minimum practical transaction size. The reversibility of transactions becomes a problem when a provider has delivered non-reversible services.
Consumers frequently buy low-cost items on the web, such as $5 keychains and $10 eyeglasses. However, bank involvement costs a lot and these costs are passed on to consumers through transaction fees and other charges. Consider all the mediation and litigation expenses that pile up in a given year and you can see that transaction costs can be significant. Moreover, if a provider completes a service he should rightfully get paid. But the current system allows transactions to be reversed, putting a service provider at risk of not getting paid.
[if !supportLists]· [endif]The possibility of a transaction's reversal hangs over everyone. And that requires people to trust a third party such as banks to resolve payment disputes.
Many merchants and consumers don't want to trust a financial institution. They're expensive; may not be trustworthy; are frequently hacked; and often give too much information to the government without informing the affected party. All this also create privacy concerns. In this section, Nakamoto outlines the limitations of the traditional payment system, and he is setting up the audience for his proposed solutions.
[if !supportLists]· [endif]The system accepts a certain percentage of fraud as unavoidable. Nonetheless, fraud increases everyone's cost of doing business. Nakamoto proposes an electronic payment system that is based on cryptographic proof instead of trust.
Cryptography involves the use of code and protocols to establish secure communications.
Such a system would let two parties transact directly with each other. The new method, namely Bitcoin, features the following:
[if !supportLists]1. [endif]Peer-to-peer payments over an online network.
[if !supportLists]2. [endif]The elimination of third parties and replacing trust with verification.
[if !supportLists]3. [endif]Transactions would be irreversible and Nakamoto argues that irreversibility would protect sellers from fraud. Escrow mechanisms can be implemented to protect buyers.
[if !supportLists]4. [endif]A peer-to-peer distributed timestamp server would generate mathematical proof of the chronological order of transactions. The system is secure so long as honest participants collectively control more computing power than attackers/hackers.
Nakamoto believes that it's better to verify transactions rather than trust an external third party, especially when it comes to something as important as money. The irreversibility of transactions provides confidence that the payment system as a whole is robust. Secondly, irreversibility minimizes fraud, he argues. Decentralized computers would prove the exact order of these irreversible transactions, creating user confidence that the records in the electronic audit trail, the blockchain, are valid and accurate.
2. Transactions
In this section, Nakamoto's description of the electronic transaction process, namely the blockchain, gets technical. In simple terms, he defines an electronic "coin" as a chain of digital signatures. Owners digitally sign a hash of the previous transaction and add a public key of the next owner to the end of the coin. A recipient of the coin, a payee, can verify the signatures in order to verify the chain of ownership.
A Bitcoin doesn't exist anywhere per se, at least not in the traditional sense of physical cash. Rather, Nakamoto's concept of an electronic "coin" is a chronological series of verified digital signatures. To illustrate, think of Nakamoto's virtual coin as a UPS or FedEx package that you sign at your doorstep before sending it to a forwarding address. But the difference is that a publicly-available ledger is placed right on the packing slip which shows the entire history of all prior deliveries of the same package. The information includes all originating addresses as well as timestamps detailing where and when exactly each delivery took place. Such a comprehensive audit trail, he argues, would provide assurance to both recipient and the entire network that the chain of deliveries/transactions is accurate and secure.
However, Nakamoto points out a potential problem with duplicate payments. A recipient/payee can't verify that a coin's owner didn't send the same coin to other recipients/payees, which is referred to as the double-spend problem.
For example, John owns only one Bitcoin but sends one coin each to two different merchants -- amounting to two Bitcoins paid with only one originating coin. To solve the double-spend problem without relying on a third party, Nakamoto says that all transactions must be publicly revealed. Secondly, all participants of the payment system must adhere to the same timeline so that everyone agrees to a single history of the order in which transactions are received.
A timeline and public history of all transactions prevent double-spending because later transactions would be considered an invalid, or perhaps fraudulent, payment from the same coin. Each coin has a unique timestamp and the earlier transaction would be accepted as the legitimate payment. One coin, one payment. Sending the same coin to a second merchant, per the above example, would show a different timestamp that occurred later in the timeline. And that would invalidate the second payment/transaction.
3. Timestamp Server
A timestamp server takes a hash of a block of items and publicly announces the hash. The timestamp proves the existence of the data at the time. Each timestamp includes the previous timestamp in its hash. And each additional timestamp reinforces the ones before it. This sequence forms a chain.
Here we see the emerging structure of the blockchain. The timestamps are key to preventing double-spending and fraud. It'd be virtually impossible to send duplicate coins because each coin contains different, chronologically-ordered timestamps. Think back to the analogy of a UPS/FedEx package. Each delivery would contain a unique timestamp on the packing slip, and that would mark the exact time of each and every delivery on the public ledger. Bitcoin's file size in bytes increases as the transaction history gets larger. And larger files lead to longer processing times. Transaction processing -- or mining -- continually require more CPU power to verify the transactions because the digital records themselves grow in size. Continuing our example, the packing slip on the same UPS/FedEx package keeps growing in size because more deliveries mean more recorded history of all deliveries ever made.
4. Proof-of-Work
Nakamoto says that proof-of-work is used to implement a peer-to-peer distributed timestamp network (mentioned above). The process scans for a value that when hashed, results in a certain numerical expression. The timestamp network must reconcile this value with a block's hash. CPU power is needed to satisfy the proof-of-work, and the block cannot be changed without redoing the work. Later blocks are chained after it, and to change the block would require redoing all the blocks after it.
The language may be technical but the concept is simple. Proof-of-work is what safeguards the blockchain. Nakamoto says that a hash created by a timestamp server is assigned a unique number that is then used to identify the hash in the blockchain. Inherent in this unique number is a math puzzle that a computer must solve before a transaction can happen. Once a correct answer is given, it serves as proof that the specified work has been done. When someone sends an electronic coin, they must take a hash's unique number and solve an inherent math puzzle. The answer is then passed to the recipient to check if the solution is correct -- an important validation step. If the answer is correct, the payment/transaction takes place and adds to the length of the blockchain. If not, the proposed transaction is rejected.
Proof-of-work provides one vote per CPU, not by IP address. Otherwise an attacker may allocate several IPs in an attempt to hack the network. Secondly, the longest chain of blocks serves as proof that the CPUs invested the greater amount of work in that longer chain. This process secures the blockchain by requiring would-be-attackers to redo the work of the block and all blocks after it (i.e., solve all those math puzzles) and then try to surpass the work of all the honest computers in the network. Nakamoto says that it'd be an extremely difficult task for an attacker to do just that, and that the probability of success diminishes exponentially the more blocks are added to a chain.
So how does proof-of-work protect the blockchain? In layman's terms, honest CPUs in the network solve each hash's math problem. As these computational puzzles are solved, these blocks are bundled into a chronologically-ordered chain. Thus the term blockchain. This validates to the entire system that all the required "math homework" has been completed. An attacker would have to redo all the completed puzzles and then surpass the work of honest CPUs in order to create a longer chain -- a feat that would be extremely unlikely if not impossible. This sequence makes Bitcoin transactions irreversible. Nakamoto points out that honest nodes in the network need to collectively possess more CPU power than an attacker.
5. Network
Nakamoto outlines the steps for running the peer-to-peer network:
[if !supportLists]1. [endif]New transactions are broadcast to all nodes/computers in the network.
[if !supportLists]2. [endif]Each node collects new transactions into a block.
[if !supportLists]3. [endif]Each node works on finding a difficult proof-of-work for its block.
[if !supportLists]4. [endif]When a node finds a proof-of-work, it broadcasts the block to all nodes.
[if !supportLists]5. [endif]Nodes accept the block only if all transactions in it are valid and not already spent.
[if !supportLists]6. [endif]Nodes express their acceptance of the block by working on creating the next block in the chain, using the hash of the accepted block as the previous hash.
As mentioned in earlier sections, nodes always consider the longest chain to be the correct one and will work on extending it.
This section shows why it's important to announce transactions to all nodes. It forms the basis for verifying the validity of each transaction as well as each block in the blockchain. As mentioned earlier, each node solves a proof-of-work puzzle and thus always recognizes the longest chain to be the correct version. As time progresses, the blockchain's record grows and provides assurance to the entire network of its validity.
6. Incentive
The first transaction in a block is a special transaction that starts a new coin owned by the creator of the block. This achieves two things. First, the creation of a new coin rewards nodes/computers to support the network. Second, it's a way to initially distribute new coins into circulation since there is no central authority to issue them. The new coin rewards nodes -- aka Bitcoin miners -- for expending their time, CPU and electricity to make the network possible. They can also be rewarded with transaction fees. Nakamoto envisions a limited number of coins to ever enter circulation, at which point miners can be incentivized solely by transaction fees that are inflation-free. New coins also incentivize nodes to play by the rules and remain honest. An attacker would have to expend a ton of resources to threaten the system, and getting rewarded by coins and transaction fees serve as a deterrent to such fraud.
Mining gold requires labor, water and equipment and it's an activity similar to Bitcoin mining. The miners of electronic coins process transactions, for which they are rewarded with new Bitcoins and/or transaction fees. Since a maximum of 21 million Bitcoins will ever be mined, the system can be free of inflation. Therefore, Bitcoin can serve as a sustainable store of value, similar to gold. Compare that to fiat currency, such as the U.S. dollar. Due to inflation, the dollar has devalued nearly 97 percent since 1913. Bitcoin's incentive program is a mechanism that protects the peer-to-peer electronic payment system. The issuance of new Bitcoin as well as transaction fees keep nodes honest. Because it wouldn't be worth it to attack the very system that forms the foundation of their wealth. As the saying goes, you don't bite the hand that feeds you.
7. Reclaiming Disk Space
To save disk space, Nakamoto says that nodes can discard data from old transactions, with only the root of the discarded transaction kept in the block's hash. This enables the blockchain to remain intact, albeit with less data from old transactions. He briefly describes a process for compacting data. But with Moore's Law, Nakamoto says that the future capacity of computer hardware should be sufficient to operate the network without miners having to worry about storage space.
8. Simplified Payment Verification
In this section, Nakamoto provides a technical explanation of how to verify payments without running a full network node. That requires getting the longest proof-of-work chain and checking if the network has accepted it. The verification is reliable as long as honest nodes control the network. But an attacker can create fraudulent transactions for as long as an attacker can overpower the network. One defense against an attack is for network nodes to broadcast alerts when they detect an invalid block. Such an alert could prompt a user's software to download the full block as well as alerted transactions in order to confirm the inconsistency. Nakamoto adds that businesses that receive frequent payments may want to consider operating their own nodes to achieve more independent security and quicker verification.
There are non-Bitcoin blockchain protocols that large companies are applying outside finance. For example, a company can create an invite-only protocol that selects certain parties to participate in a private network of nodes. The point is, there are many ways to set up a blockchain network that follows a different set of rules for verification. Nakamoto describes one way to do so for a peer-to-peer payment system, but he says that businesses may want to adapt their processes based on their own unique circumstances.
9. Combining and Splitting Value
Combining transaction amounts will result in more efficient transfers as opposed to creating a separate transaction for every cent involved.
In other words, it'd be simpler and more efficient to send three Bitcoins in a single transaction rather than create three transactions of one Bitcoin each, assuming the coins are sent to the same recipient.
To allow transaction values (amounts) to be split or combined, transactions can contain multiple inputs and outputs. There can be single or multiple inputs. But there can only be a maximum of two outputs: one for the payment, and one returning the change, if any, back to the sender.
This process enables payments with specific amounts. A sender can send Bitcoin payment to another party and get back his/her change, if needed.
10. Privacy
With traditional payments, users attain privacy when banks limit information available to the parties involved as well as the third party. With the peer-to-peer network, privacy can still be achieved even though transactions are announced. This is accomplished by keeping public keys anonymous. The network may be able to see payment amounts being sent and received, but transactions are not linked to identities. Additionally, Nakamoto proposes that a new private key should be used for each transaction to avoid payments being linked to a common owner.
To maintain privacy, Nakamoto says it's important for public keys to keep a user's identity anonymous. While everyone may be able to see transactions, no identifiable information is distributed.
11. Calculations
It's highly unlikely for an attacker to create an alternate chain faster than an honest chain. Nodes won't accept an invalid transaction or blocks containing them. Moreover, an attacker is limited in what he can attempt to do: He can only try to change one of his own transactions to retrieve coins he recently spent. The probability that an attacker succeeds drops exponentially the more valid blocks are added to the chain. Nakamoto says that an attacker would have to get lucky early on to have a remote chance. Moreover, a receiver creates a new public key and gives it to a sender shortly before signing. This makes it difficult for an attacker to execute a fraudulent transaction through a parallel chain.
There's a higher probability that an honest node will find a block faster than an attacker. It'd be extremely difficult for an attacker to solve several proof-of-work puzzles in a row faster than the rest of the honest nodes. Every 10 minutes, there are new puzzles being solved by nodes in the network.
12. Conclusion
The peer-to-peer system for electronic payments relies on a distributed network of honest nodes to validate transactions. Validation replaces the need to trust expensive third parties such as banks. The electronic coins are made from digital signatures, and proof-of-work that form the blockchain prevent double-spending. The system stays secure so long as honest nodes control more CPU power than an attacker. Moreover, the nodes accept longer blocks as valid and work on extending them. This protocol rejects invalid blocks, and potential fraud, in the process. Rules and incentives can be enforced using a voting system.
In the final section, Nakamoto says that "The network is robust in its unstructured simplicity." Yes indeed!
Smart blockchain cloud storage and Filecoin cooperate with IPFSprotocol and IPFS technology enterprises
比特币白皮书：初学者指南
文章提供：灵动区块链云存储
比特币白皮书，比特币：对等电子现金系统，由中本聪于2008年出版。比特币正在革新全球支付行业，世界各地的人们都在重新思考他们的钱的含义。此外，处理比特币交易的基础技术和网络称为区块链，正在改变着银行，农业，物流，医疗，选举和制造业等众多行业。中本聪（Satoshi Nakamoto）在2008年发表的开创性工作使所有这些成为可能，概述了原始比特币白皮书中介绍的比特币及其工作原理。
灵动区块链云存储建议先看看指南
如何使用本指南
Bitcoin.com提供了对Nakamoto作品的简化解释。我们为白皮书的所有12个部分提供注释。斜体文字用于提供注释和注释，以区分作者的观点和中本聪的观点。
1.简介
比特币创造者中本聪讨论了网络对可信赖的第三方（如银行和信用卡公司）的依赖，以处理电子付款。传统方法可能适用于大多数交易，但是当金融机构促进互联网上商品的买卖时，确实会出现问题。以下是涉及第三方的传统电子支付的一些弱点：
[if !supportLists]· [endif]由于银行必须调解不可避免出现的纠纷，因此交易可以撤消。
想想通常在商家，消费者和其他方（例如付款处理方，PayPal或税务机关）之间发生的纠纷。
[if !supportLists]· [endif]银行的干预（即调解）增加了交易成本，这也限制了最小实际交易规模。当提供商提供了不可逆服务时，交易的可逆性就成为一个问题。
消费者经常在网上购买廉价商品，例如5美元的钥匙扣和10美元的眼镜。但是，银行的参与成本很高，这些成本通过交易费和其他费用转嫁给消费者。考虑在给定年份中累积的所有调解和诉讼费用，您会发现交易成本会很大。此外，如果提供者完成了一项服务，他应该得到合理的报酬。但是，当前的系统允许撤销交易，使服务提供商面临无法获得付款的风险。
[if !supportLists]· [endif]交易逆转的可能性笼罩着所有人。这就要求人们信任银行等第三方来解决支付纠纷。
许多商人和消费者都不想信任金融机构。它们很贵；可能不值得信赖；经常被黑客入侵；并且经常向政府提供过多信息而没有通知受影响的一方。所有这些还引起隐私问题。在本节中，Nakamoto概述了传统支付系统的局限性，他正在为提出的解决方案吸引受众。
[if !supportLists]· [endif]系统接受不可避免的一定百分比的欺诈。但是，欺诈会增加每个人的经商成本。Nakamoto提出了一种基于密码证明而非信任的电子支付系统。
密码学涉及使用代码和协议来建立安全的通信。
这样的系统将使两个当事方彼此直接进行交易。新方法，即比特币，具有以下特点：
[if !supportLists]1. [endif]在线网络上的对等支付。
[if !supportLists]2. [endif]消除第三方并用验证代替信任。
[if !supportLists]3. [endif]交易将是不可逆的，中本聪认为不可逆将保护卖方免受欺诈。可以实施托管机制来保护买家。
[if !supportLists]4. [endif]对等分布式时间戳服务器将生成事务按时间顺序排列的数学证明。只要诚实的参与者共同控制比攻击者/黑客更多的计算能力，该系统就是安全的。
中本聪认为，验证交易比信任外部第三方要好，尤其是在涉及金钱等重要问题时。交易的不可逆转性使我们确信支付系统整体上是稳健的。其次，他认为不可逆转可以最大程度地减少欺诈。分散的计算机将证明这些不可逆交易的确切顺序，从而使用户确信电子审计跟踪（区块链）中的记录是有效和准确的。
2.交易
在本节中，中本聪对电子交易流程（即区块链）的描述具有技术性。简单来说，他将电子“硬币”定义为数字签名链。所有者以数字方式签署上次交易的哈希值，并添加一个公钥下一位拥有者的身份，直到硬币结束。硬币的接收者（收款人）可以验证签名，以验证所有权链。
比特币本身并不存在，至少在传统的有形现金中并不存在。确切地说，中本聪的电子“硬币”概念是按时间顺序排列的一系列经过验证的数字签名。为说明起见，请将Nakamoto的虚拟硬币视为UPS或FedEx包裹，您在将其发送到转发地址之前先在门口签名。但是不同之处在于，在装箱单上放置了一个公开可用的分类帐，该分类帐显示了同一包裹之前所有交货的全部历史记录。该信息包括所有始发地址以及详细说明每次交付的时间和地点的时间戳。他认为，这样全面的审计跟踪将为收件人和整个网络保证交付/交易链的准确性和安全性。
但是，中本聪指出重复付款有潜在的问题。收款人/收款人无法验证硬币的所有者没有将相同的硬币发送给其他收款人/收款人，这被称为双花问题。
例如，约翰只拥有一个比特币，但每个都向两个不同的商人发送一个硬币-总计只有一个原始硬币支付了两个比特币。 为了解决不依赖第三方的双重支出问题，中 本聪表示，所有交易都必须公开披露。其次，支付系统的所有参与者必须遵守相同的时间表，以便每个人都同意接受交易的订单的单一历史记录。
所有交易的时间表和公共历史记录可防止重复支出，因为以后的交易将被视为用同一硬币进行的无效或欺诈性付款。每个硬币都有唯一的时间戳，较早的交易将被视为合法付款。一枚硬币，一付。按照上面的示例，将相同的硬币发送给第二个商人将显示不同的时间戳，该时间戳发生在时间轴的后面。这样会使第二笔付款/交易无效。
3.时间戳服务器
时间戳服务器对项目块进行散列并公开宣布该散列。时间戳证明了当时数据的存在。每个时间戳在其哈希中均包含前一个时间戳。并且每增加一个时间戳都会增强之前的时间戳。该序列形成一条链。
在这里，我们看到了区块链的新兴结构。时间戳是防止重复支出和欺诈的关键。发送重复的硬币几乎是不可能的，因为每个硬币包含不同的，按时间顺序排列的时间戳。回想一下UPS / FedEx包裹的类比。每次交货将在装箱单上包含唯一的时间戳记，并将在公共分类帐上标记每次交货的确切时间。 随着交易历史记录的增加，比特币的文件大小（以字节为单位）会增加。较大的文件导致更长的处理时间。事务处理（或挖掘）不断需要更多的CPU能力来验证事务，因为数字记录本身会不断增长。继续我们的示例，同一UPS / FedEx包装上的装箱单尺寸不断增加，因为更多的交付意味着有史以来所有交付的记录越多。
4.工作量证明
中本聪说，工作量证明被用于实现对等分布式时间戳网络（如上所述）。该过程将扫描一个值，该值在经过哈希处理后会生成特定的数值表达式。时间戳网络必须将此值与块的哈希值进行协调。需要CPU能力来满足工作量证明，并且如果不重做工作就无法更改块。后面的块链接在其后，要更改该块，将需要重做其后的所有块。
语言可能是技术性的，但概念很简单。工作量证明是保护区块链的要素。中本聪说，由时间戳服务器创建的哈希被分配了一个唯一的编号，该编号随后被用于识别区块链中的哈希。这个唯一的数字是一个数学难题，计算机必须先解决数学难题，然后才能进行交易。给出正确答案后，就可以证明已完成指定的工作。 当某人发送电子硬币时，他们必须获取哈希的唯一编号并解决固有的数学难题。然后将答案传递给收件人，以检查解决方案是否正确-这是重要的确认步骤。如果答案是正确的，则进行支付/交易并增加区块链的长度。如果不是，则提议的交易被拒绝。
工作量证明为每个CPU提供一票，而不是IP地址。否则，攻击者可能会分配多个IP，以试图入侵网络。其次，最长的块链可以证明CPU在该较长的链中投入了大量的工作。该过程要求要求攻击者重做块及其之后的所有块的工作（即解决所有这些数学难题），然后尝试超越网络中所有诚实计算机的工作，从而保护了区块链。Nakamoto表示，做到这一点对于攻击者而言将是一项极其艰巨的任务，成功的概率将随着链中添加的更多区块而呈指数下降。
那么工作量证明如何保护区块链呢？用外行的话来说，网络中诚实的CPU解决了每个哈希的数学问题。解决了这些计算难题后，这些块便按时间顺序捆绑在一起。因此，术语区块链。这向整个系统验证了所有必需的“数学作业”已经完成。攻击者必须重做所有已完成的难题，然后超越诚实的CPU的工作才能创建更长的链-这一壮举是极不可能的，即使不是不可能的。此序列使比特币交易不可逆。中本聪指出，网络中的诚实节点需要集体拥有比攻击者更多的CPU能力。
5.网络
Nakamoto概述了运行对等网络的步骤：
[if !supportLists]1. [endif]新交易将广播到网络中的所有节点/计算机。
[if !supportLists]2. [endif]每个节点将新交易收集到一个块中。
[if !supportLists]3. [endif]每个节点都在为其块寻找困难的工作量证明。
[if !supportLists]4. [endif]当节点找到工作量证明时，它会将块广播到所有节点。
[if !supportLists]5. [endif]节点仅在块中的所有事务有效且尚未使用时才接受该块。
[if !supportLists]6. [endif]节点通过使用接受的块的散列作为前一个散列来创建链中的下一个块，从而表达对块的接受。
如前面各节所述，节点始终将最长的链视为正确的链，并将继续对其进行扩展。
本节说明了为什么向所有节点宣布事务很重要。它构成了验证每个交易以及区块链中每个区块有效性的基础。如前所述，每个节点解决了工作量证明难题，因此始终将最长的链识别为正确的版本。随着时间的流逝，区块链的记录不断增长，并为整个网络的有效性提供保证。
6.激励
区块中的第一笔交易是一种特殊交易，它启动了区块创建者拥有的新硬币。这实现了两件事。首先，创建新硬币会奖励节点/计算机以支持网络。其次，由于没有中央机构来发行新硬币，因此这是一种初始分配新硬币流通的方式。新硬币奖励节点-aka比特币矿工-花费时间，CPU和电力来使网络成为可能。他们也可以得到交易费用的奖励。中本聪设想，有少量硬币将进入流通领域，届时，仅通过无通货膨胀的交易费用就可以激励矿工。新币也激励节点遵守规则并保持诚实。攻击者必须花费大量资源来威胁系统，
开采黄金需要劳力，水和设备，其活动类似于比特币开采。电子硬币的矿工处理交易，为此他们将获得新的比特币和/或交易费。由于将最多开采2100万个比特币，因此该系统可以避免通货膨胀。因此，比特币可以像黄金一样充当可持续的价值存储。将其与法定货币（例如美元）进行比较。由于通货膨胀，自1913年以来，美元贬值了近97％。 比特币的奖励计划是一种保护对等电子支付系统的机制。新比特币的发行以及交易费用使节点保持诚实。因为攻击构成其财富基础的系统是不值得的。俗话说，你不咬你的手。
7.回收磁盘空间
为了节省磁盘空间，中本聪说，节点可以丢弃旧事务中的数据，而被丢弃事务的根仅保留在块的哈希中。这使区块链保持完整，尽管来自旧交易的数据更少。 他简要介绍了压缩数据的过程。但是，根据摩尔定律，中本聪说，未来计算机硬件的容量应足以运行网络，而矿工不必担心存储空间。
8.简化的付款验证
在本节中，Nakamoto提供了有关如何在不运行完整网络节点的情况下验证付款的技术说明。这就需要获得最长的工作量证明链，并检查网络是否接受了它。只要诚实节点控制网络，验证就可靠。但是，只要攻击者可以控制网络，攻击者就可以创建欺诈性交易。一种针对攻击的防御措施是让网络节点在检测到无效块时广播警报。这样的警报可以提示用户的软件下载完整的块以及警报的交易，以确认不一致。Nakamoto补充说，收到频繁付款的企业可能希望考虑运营自己的节点以实现更独立的安全性和更快的验证。
大公司正在应用外部财务的非比特币区块链协议。例如，公司可以创建仅邀请协议，该协议选择某些参与方以参与节点的专用网络。关键是，有许多方法可以建立遵循不同验证规则集的区块链网络。Nakamoto描述了一种对等支付系统的实现方法，但他说，企业可能希望根据自己的独特情况调整其流程。
9.合并和分割价值
合并交易金额将导致更有效的转帐，而不是为所涉及的每一分钱创建单独的交易。
换句话说，假设将硬币发送给同一接收者，则在一次交易中发送三个比特币将比创建每个比特币的三个交易更简单，更有效。
为了允许拆分或合并交易值（金额），交易可以包含多个输入和输出。可以有一个或多个输入。但是最多只能有两个输出：一个用于付款，一个用于将更改（如果有）退还给发件人。
此过程可实现特定金额的付款。发件人可以将比特币付款发送给另一方，并在需要时取回其更改。
10.隐私权
使用传统支付方式，当银行限制相关方和第三方可以使用的信息时，用户可以获得隐私。使用对等网络，即使宣布了交易，仍然可以实现隐私。这可以通过使公用密钥保持匿名来实现。网络可能能够看到正在发送和接收的付款金额，但是交易未链接到身份。此外，中本聪建议对每笔交易都应使用新的私钥，以避免将付款链接到共同所有者。
为了维护隐私，中本聪说，公共密钥必须使用户的身份匿名，这一点很重要。尽管每个人都可以看到交易，但不会分发任何可识别的信息。
11.计算
攻击者极不可能以比诚实链更快的速度创建备用链。节点将不接受无效的事务或包含它们的块。此外，攻击者的尝试能力受到限制：他只能尝试更改自己的交易之一来检索他最近花费的硬币。攻击者成功的概率呈指数级下降，将更多有效块添加到链中。中本聪说，攻击者必须尽早获得幸运，才能有一个很小的机会。此外，接收者会在签名前不久创建一个新的公共密钥，并将其提供给发送者。这使得攻击者很难通过并行链执行欺诈性交易。
诚实节点比攻击者更快找到块的可能性更高。对于攻击者而言，比其他诚实节点更快地连续解决几个工作量证明之谜是极其困难的。每隔10分钟，网络中的节点就会解决新的难题。
12.结论
用于电子支付的对等系统依赖于诚实节点的分布式网络来验证交易。验证取代了信任昂贵的第三方（例如银行）的需要。电子硬币由数字签名制成，形成区块链的工作量证明可防止双重支出。只要诚实的节点比攻击者控制更多的CPU能力，系统就可以保持安全。此外，节点将更长的块视为有效块并致力于扩展它们。该协议在此过程中拒绝无效的块和潜在的欺诈。可以使用投票系统来执行规则和激励措施。
在最后一节中，中本聪说：“网络具有非结构化的简单性，因此非常健壮。” 确实是的！
灵动区块链云存储与Filecoin合作以IPFS协议与IPFS技术的企业
网友评论