有关BitCoin的介绍Introduction to BitCoin

中文翻译部分（一） 英文见附后

有关BitCoin的介绍

忘记那些你曾经听说过的.  许多人发现BitCoin有许多有用的价值，但通常他们都误解了其中的意思，如：“BitCoin能利用电脑获得免费的钱”或者“为了不让我电脑运行程序浪费无谓的电力而使用BitCoin”诸如此类。本文将着重什么是 BitCoin，以及 BitCoin 解决了什么问题，帮助你很好的归纳并大体上理解BitCoin。大部分网站都不能很好的理解这两个问题，自然也就很难评价BitCoin这种技术所带来的效果。

什么是BitCoin：BitCoin利用21万个数学令牌的协议作为社区中的钱，类似于古时候非洲或亚洲的社会所用的贝壳钱。与贝壳钱不一样的是


   BitCoin的数量不会增加
   BitCoin不能伪造
   BitCoin可以分割成无限小块
   BitCoin可以以数据连接（例如：英特网）的方式迅速的进行远距离传输

    这项工作是利用强大的加密功能多次加密（甚至比银行加密的算法还要强大）来完成的。不同于简单的“发送”硬币：利用签名加密一个实体到另一个实体的过程。BitCoin算法的本质是利用在多个地方放置锁和密钥来备份BitCoin，所以复制BitCoin并不会增加你拥有BitCoin的数量。

    正因为BitCoin的价值是由社区所决定的，所以它们并不需要通过他人接受或任何权力机构的支持下取得成功的。它对全球来说，它就像一个当地货币，并且比当地货币更具影响力、更具当地性。用一个案例来说明社区如何“支持”使得BitCoin有价值；
在2011年4月4日30,000 个BitCoins在最大的BitCoin交易中被抛售，抛售了几乎所有“买入”的BitCoin，使得其价格几乎跌到原先的1/3。但是，几天之后，交易价格却已经全面反弹回原来的价格，BitCoin通过大量的买入抵消之前消耗的贸易的抛售，又重新回到了良好的交易量。BitCoin在如此小的经济（当前只有5百万个BitCoins在总额为2100万的BitCoins中流通，按照当时的汇率换算成美元约为3,750,000$）中吸收了如此之大的廉价抛售而不被摧毁，显示出BitCoin机制能够完美的运行。

BitCoin解决了什么问题：从数学的角度来看，Bitcoin协议的具体实施解决了“如何在不适用任何信任机制完成这一切”。这听起来不可思议，但它的确做到了。通常来说，本国流通货币必须信任（使用它）的每一个人才能工作，国家货币也一样（national currency和local currency有何不同？national 比local 的范围要大，local可以指当地的）在两者中，信任通常被滥用，但通过BitCoin体制，任何人都不可以滥用其信任体制，没有人能够无限的印钞，没有人能够通过简单的仿制来使用假币，更不能绕过本人访问权限的密钥的情况下使用他人货币。人们想要单纯地打破这数学规则去创造一个完全不同的体制，那是无法实现的。只要有人遵循这个规则，唯一能破坏BitCoin体制的方法就只有当所有人都不使用它。

    这种不需要信任任何人的不可思议的机制通过两种方法实现：第一，通过尖端的加密技术来完成，加密技术确保只有Bitcoin的拥有者才有权利消费他们。在Bitcoin中的加密技术非常的强大，以至于所有的在线银行都会向Bitcoin妥协（其他的在线银行被危害的时候，bitcon 还是好好的）。若这事情发生了，它甚至会升级。这就像你钱包里的每个钞票都有100个数据的锁锁在一起，除非你销毁账单自己，否则它不能被移除。BitCoin就是如此的安全。

    于此同时，第二种安全措施，叫做环块链，这才是真正神奇的地方。环块链是简单的、权威的记录。用于确认交易是否在点对点的Bitcoin网络上。即使遇到了先进的数据解密，如果没有中央记录确认Bitcoin被“支付”给某些人，你不能给多个人签同一个硬币，这就是所谓的double-spend attack，就像写一张透额的支票，而实际你账户并没有那么多钱。通常这种行为都由中央信任机构--银行，来阻止，也就是银行不停的追踪所有的你写的支票以及确认它们不会超过你所拥有的钱。即使这样，大部分人也只会在真正信任你的情况下接受支票，同时银行必须得花费大量的金钱为储存在物理上的或数据上的中央记录提供物理上的保护。更不用说有些银行的职员利用他们的职务之便滥用信任体系。同时，在传统的银行系统中，银行不会按照规矩办事---它可以借出的钱比它实际拥有的钱多。

    环块链通过创造主要的档案解决了以上所有的问题。这个档案记录一个已加密的安全的BitCoin的传送，对他们进行验证，同时锁定在一个高竞争力的市场—mining。作为回报，Bitcoin社区以一系列的block/Bitcoin作为奖励给miners， 那取自于最先的有限的bitcon，而这是事先已约定好的。Bitcon 送完后，费用将代替bitcon 奖励给优先者，在一个竞争更大的市场确保最低的可能消费。  上述交易进行了验证并锁定由采矿计算工作在一个非常特殊的方式，所以，没有一个人能够通过不在网络中做任何的计算工作来累积miners从而改变这种官方的交易记录。

    总结：这一切的数学技术听起来可能有点拗口的，但它实际上意味着 BitCoin能像现金一样工作。 Bitcoin交易是故意 不可逆的 -不像信用卡或PayPal在可以使已经扣款的情况下使之无效。 而且有没有中间商 。 交易在发送方和接收方之间以网络点对点的方式之间完成

    由于BitCoin的复杂设计， 网络仍然是安全的，无论在哪里，你都可以进行bitcoin交易 。 这是难以置信的-从没有人尝试建立一个这样的系统！ 在这之前所有货币系统依靠信任的人 ，无论是国王，市政厅，联邦储备或银行。 BitCoin没有。 它以数学方法为担保，而不是法律，这就是为什么技术人员和经济学家都为之兴奋。 

英文原稿（二）

Introduction to BitCoin

Forget most things you've heard.  People discover BitCoin in a variety of ways, but usually pick up some sort of misconception like "BitCoin gives free money to people with computers" or "in order to use BitCoin I have to use a program that wastes electricity for nothing" along the way.  Here is a good summary to help you understand BitCoin in general, by focussing on what BitCoin is and what problem it solves.  These two things are not typically well explained on most websites, and it is difficult to appreciate just how effective a technology BitCoin is until they are understood.

What BitCoin is:  An agreement amongst a community of people to use 21 million secure mathematical tokens--"bitcoins"--as money, like traditional African and Asian societies used the money cowry.  Unlike the money cowry:

• there will never be more bitcoins
• they are impossible to counterfeit
• they can be divided into as small of pieces as you want
• and they can be transferred instantly across great distances via a digital connection such as the internet.

This is accomplished by the use of powerful cryptography many times stronger than that used by banks.  Instead of simply being "sent" coins have to be cryptographically signed over from one entity to another, essentially putting a lock and key on each token so that bitcoins can be securely backed up in multiple places, and so that copying doesn't increase the amount you own.

Because bitcoins are given their value by the community, they don't need to be accepted by anyone else or backed by any authority to succeed.  They are like a local currency except much, much more effective and local to the whole world.  As an example of how effective the community is at "backing" the bitcoin: on April 4th 201130,000 bitcoins were abruptly sold on the largest BitCoin exchange, consuming nearly all "buy" offers on the order book and dropping the price by nearly 1/3.  But within a couple of days, the price on the exchange had fully rebounded and bitcoins were again trading at good volumes, with large "buy" offers slowly replacing the ones consumed by the trades.  The ability of such a small economy (there were only 5 million out of the total 21 million bitcoins circulating then, or about 3.75 million USD worth at then-current exchange rates) to absorb such a large sell-off without crashing shows that bitcoins were already working beautifully.

What problem BitCoin solves:  Mathematically, the specific implementation of the bitcoin protocol solves the problem of "how to do all of the above without trusting anyone".  If that sounds amazing, it should!  Normally a local currency has to trust all kinds of people for it to be able to work.  So does a national currency.  And in both cases, that trust is often abused.  But with BitCoin, there's no one person who can abuse the system.  Nobody can print more money, nobody can re-use the coins simply by making a copy, and nobody can use anyone else's coins without having direct access to their keys.  People who break its mathematical "rules" simply end up creating a whole different system incompatible with the first.  As long as these rules are followed by someone, the only way BitCoin can fail is for everyone to stop using it.

This marvelous quality of not having to trust anyone is achieved in two ways.  First, through the use of cutting-edge cryptography.  Cryptography ensures that only the owner of the bitcoins has the authority to spend them.  The cryptography used in BitCoin is so strong that all the world's online banking would be compromised before BitCoin would be, and it can even be upgraded if that were to start to happen.  It's like if each banknote in your pocket had a 100-digit combination lock on it that couldn't be removed without destroying the bill itself.  BitCoin is that secure.

But the second way of securing the system, called the blockchain, is where the real magic happens.  The blockchain is a single, authoritative record of confirmed transactions which is stored on the peer to peer bitcoin network.  Even with top-notch digital encryption, if there was no central registry to show that certain bitcoins had already been "paid" to someone else, you could sign over the same coins to multiple people in what's called a double-spend attack, like writing cheques for more money than you have in your account.  Normally this is prevented by a central authority, the bank, who keeps track of all the cheques you write and makes sure they don't exceed the amount of money you have.  Even so, most people won't accept a cheque from you unless they really trust you, and the bank has to spend a lot of money physically protecting those central records, whether they are kept in a physical or digital form.  Not to mention, sometimes a bank employee can abuse their position of trust.  And, in traditional banking, the bank itself doesn't have to follow the rules you do--it can lend out more money than it actually has.

The blockchain fixes all these problems by creating a single master registry of the already-cryptographically-secured bitcoin transfers, verifying them and locking them down in a highly competitive market called mining.  In return for this critical role, the BitCoin community rewards miners with a set amount of bitcoins per block, taken from the original limited quantity on a pre-agreed schedule.  As that original amount gradually runs out, this reward will be replaced by fees paid to prioritise one transaction over another--again in a highly competitive market to ensure the lowest possible cost.  The transactions are verified and locked in by the computational work of mining in a very special way so that no one else can change the official record of transactions without doing more computational work than the cumulative work of all miners across the whole network.

In conclusion:  All this mathematical technology may be a bit of a mouthful, but what it means in practice is thatBitCoin works just like cash.  Bitcoin transactions are intentionally irreversible--unlike credit cards or PayPal where chargebacks can invalidate a payment that has already been made.  And there are no middlemen.  Transactions are completed directly between the sender and the receiver via the peer to peer network.

Because of BitCoin's intricate design, the network remains secure no matter where or how you process bitcoin transactions.  Which is incredible--no one else has ever tried to create a system that worked this way!  All previous monetary systems have relied on trusting somebody, whether it was the king, town hall, the federal reserve, or banks.  BitCoin doesn't.  It's guaranteed instead by the laws of mathematics, and that's why it has everyone from technologists to economists very excited.  I'm sure you have lots more questions, so scan the index below to see if they've been asked before, then dive in!  The so-called "canonical" threads linked from this index are considered newbie-friendly zones; outside of them you're welcome to try your own luck.