澄清一些对比特币的误解(适合新手)

比特币社区都是些是各种无政府主义者/阴谋理论家/奉行金本位的胆小鬼

有些是，但是社会不就是由持有各种意识形态立场的人群构成的么？

只要有足够的计算能力就可以接管整个网络

参见Weaknesses。

也就是说，随着网络的增长，个体越来越难实施这个办法。就现在来说，比特币网络的计算能力已经不比世界上最快的超级计算机差了。

就算攻击者一次性接管了整个网络，他也做不了什么大事。他没办法拿走所有人的钱。顶多能将自己的近期付款追回来，或者让他人因为得不到确认而无法付款。这种攻击相当耗资源，为了这点儿蝇头小利。。。谁会做这种赔本的买卖。

比特币犯法的

哪条？

参见法定货币的问题。

Fractional reserve banking is not possible

It is possible. There is no fundamental difference between classical currencies and bitcoin as it applies to banking. Banks will still be free to take in bitcoins and present them to customers as "available for withdrawal" while still lending most of those bitcoins to a different customer for a profit. Some of those bitcoins will be held in reserves in case of a bank run. It will be up to the bank to hold a sufficient supply of reserves in order to prevent insolvency in the event of a bank run. Central banks were established to enforce reserve requirements and so, with bitcoin lacking a central bank, some banks will almost surly collapse, taking their customers' deposits with them.

See Fractional reserve banking.

Conventional banks in the United States guarantee that account holders can withdraw 100% of their dollars based on their "word" and the fact that they are backed up by the FDIC. This program insures depositors up to a certain amount (currently $250K USD per depositor). The FDIC is widely known to have reserves sufficient to cover only a very small fraction of the total deposits it insures though the FDIC itself can be considered to be backed up by the US Congress in the event of its insolvency. After politically desired, the FDIC's role could be extended to insure Bitcoin banks and establish a minimum reserve requirement. Such a change would only happen after public outrage occurs after the inevitable collapse of major Bitcoin banks.

Because Fractional Reserve Banking is possible with bitcoins, the money supply of bitcoins (which includes demand deposits) can greatly exceed 21 million.

要等十分钟才能确认，用比特币在端点销售机神马的付款不给力啊

发款要等几十分钟才能被“确认”，这一特性将来也不会改变。即使将来网络计算的能力比现在大很多，产生一个区块的难度也会自动调整到一小时6个。要想在超市刷比特币的可能办法：

1) 小额付款，假定消费者不会诈骗就行。如果人家只买桶牛奶，看到付款就可以拿走。The transaction should propagate through the network almost instantly, allowing the seller to see the transaction within seconds (albeit with zero confirmations.) The cost of a double-spend attack should make small-scale fraud not worthwhile.

2) Utilize a 'listening' period prior to rendering the service or good. This has yet to be formally implemented in the standard bitcoin client, but would allow a vendor to receive the transaction and then monitor the bitcoin network for a certain period of time (maybe 10 seconds) for possible double spends. Vendors might utilize specialized payment processors with multiple well-connected nodes for this purpose. As explained by Satoshi, the network nodes only accept the first version of a transaction they receive to incorporate into the block they're trying to generate. When you broadcast a transaction, if someone else broadcasts a double-spend at the same time, it's a race to propagate to the most nodes first. If one has a slight head start, it'll geometrically spread through the network faster and get most of the nodes. Therefore, the longer the listening period goes without a double spend attempt, the far less likely a double-spend attempt will actually succeed. If a double-spend is detected, the vendor is notified: no latte.

3) Create a network of transaction hubs. These entities would communicate using a common API. They would float short-term loans between each other to facilitate instant transactions.

Imagine that Alice uses Carol's Clearinghouse as her hub, and Bob uses Dave's Anonymous Exchange. Both Alice and Bob have accounts with their respective hubs, and have already deposited some Bitcoins in their accounts. When Alice wants to buy a latte from Bob at a point of sale, Alice tells Carol "I want to send Bob x Bitcoins. He uses Dave's Anonymous Exchange." After checking that Alice's account does contain at least x Bitcoins, Carol sends a message to Dave, saying "Credit Bob's account with x bitcoins immediately; I'll send you the real Bitcoins in the next block." Bob instantly sees his balance increase, and gives Alice her latte.

As always, trust is required - Alice has to trust Carol, and the hubs have to trust each other. Due to competition, various hubs could develop with vastly different fee structures, membership requirements, trustability, etc.

(But the point of bitcoin is you don't need trust to execute the transaction, in the above description of option 3 you replaced the bitcoins with a trust-based centralized authority.)

等币都挖光了谁还愿意打包啊

在所有的比特币都被挖光以前的某一天，打包的奖励会低于劳动付出，这时候淘金者可以从交易费中获得收益。

比特币没有内建的退款机制，好糟糕

为什么有人觉得不好: Chargebacks are useful for limiting fraud. The person handling your money has a responsibility to prevent fraud. If you buy something on Ebay and the seller never ships it, PayPal takes funds from the seller's account and gives you back the money. This strengthens the Ebay economy, because people recognize that their risk is limited and are more willing to purchase items from risky sellers.

为什么实际上是好事: Bitcoin is designed such that your money is yours and yours alone. Allowing chargebacks implies that it is possible for another entity to take your money from you. You can have either total ownership rights of your money, or fraud protection, but not both. That said, nothing prevents the creation of services overlayed on top of Bitcoin that provide fraud protection services.

The statement "The person handling your money has a responsibility to prevent fraud" is still true; the power has been shifted into your own hands. Fraud will always exist. It's up to you to only send bitcoins to trusted entities. It is possible to trust an online identity without ever knowing their physical identity; see the OTC Web of Trust.

量子计算机可以干掉比特币

是的，你拿一台量子计算机干掉它吧。比特币的安全性可以升级- 如果量子计算机真的能被造出来的话。

See the implications of quantum computers on public key cryptography here http://en.wikipedia.org/wiki/Quantum_computer#Potential

The risk of quantum computers is also there for financial institutions, like banks, because they heavily rely on cryptography when doing transactions.

开采比特币浪费能源对生态环境有害

跟把金子从地下挖出来，熔化掉，铸成条条，再埋到地下比那可差远了。更不用提盖一堆花哨的大楼，然后浪费能源印刷铸造各种法定货币，再用至少配备两名本可以干点儿别的更有创造性的工作的保安的装甲车来回倒腾之类的了。

迄今为止，比特币相较其它的交易媒介其实是相当节约资源的。

比特币汇率一天一变，商场营业员没法定价

你在假设比特币可以立即卖出弥补操作开销。If the shopkeeper's back-end expenses were transacted in bitcoins as well, then the exchange rate would be irrelevant. Larger adoption of bitcoins would make prices sticky. Future volatility is expected to decrease, as the size and depth of the market grows.

In the meantime, many merchants simply regularly pull the latest market rates from the exchanges and automatically update the prices on their websites. Also you might be able to buy a put option in order to sell at a fixed rate for a given amount of time. This would protect you from drops in price and simplify your operations for that time period.

像 Flooz 和 e-gold 一样，比特币助长犯罪，会被禁止

• 希望比特币能够增长到没有一个组织能够破坏网络的地步，或者他们能帮助它以提供更好的服务。
• 恐怖分子开飞机撞大楼，但政府并未取消民航。显然，他们认为公共利益比可能出现的坏事要来得重要。
• 刑法在不同法域之间也是不同的。

比特币会像当年的自由币（Liberty Dollars）一样会被政府做掉

Liberty Dollars started as a commercial venture to establish alternative US currency, including physical banknotes and coins, backed by precious metals. This, in and of itself, is not illegal. They were later shut down for counterfeiting and intent to fraud after the coins, which contained less than $1 worth of silver, were put into circulation with the general money supply, supposedly having a value of 1 USD. These actions were encouraged by the makers of Liberty Dollars.

Bitcoins are not necessarily equal in value to dollars or any other currency and no one is saying they are. No member of the public will be tricked into accepting a bitcoin instead of a dollar.

Of course, actually 'shutting down' the decentralized Bitcoin network is rife with its own set of difficult considerations.

比特币根本不是去中心化的，开发者可以控制软件

比特币协议最初由其发明者中本聪定义，本协议现已被矿工和用户广泛接受为标准。

虽然比特币官方客户端的开发人员仍然对比特币社区施加影响，但他们任意修改协议的能力是非常有限的。自Bitcoin 0.3版发布以后，该协议只有非常细微的变化，并始终能与社区达成一致意见。

要修改协议，比如将封包奖金从50增加到100块，无法与网络中正在使用中的客户端兼容。如果开发者发布一个客户端，多数矿工都觉得它是有害的，或者偏离了整个项目的目标，那这个客户端根本火不起来，即使有零星的用户尝试使用，他们的交易也会被整个网络拒绝。

除了“官方”比特币客户端，其它开发组也可以做自己的客户端（目前在开发中），只要这些客户端遵循比特币协议，官方客户端的开发者无法阻止他们的竞争，因为在网络中根本无法区分哪个是官方客户端。