还不懂区块链就真的晚了

要说区块链，当然要先聊比特币。

Bitcoin is the first world-famous implementation of the blockchain technology, which was designed in 2008 by Satoshi Nakamoto.

(Please note that the Japanese-like name is just a nickname of a person or a group. We have no idea yet.)

从2010年初到2017年底，比特币的价格涨了一百多万倍。同一时段内，让我们惊奇、兴奋、绝望、心碎的北京房价，涨了“区区”3倍不到。

The first real-world Bitcoin transaction was made in May 2010, when a US programmer bought a pizza with 10,000 Bitcoins (BTC). In this transaction, the value of a Bitcoin was less than 0.01 US dollars.

But in December 2017, a Bitcoin was priced at a jaw-dropping 17,900 US dollars.

这位网名Laszlo Hanyecz，人称“ the pizza guy”的程序员，在2014年2月说出了自己的感受：

Laszlo Hanyecz, the pizza programmer, said, "Nobody owes me anything...I generated my share and I spent it, it was just at a time when the value was lower, but so was the generation difficulty, and the block reward was 50."

（Hanyecz用10000比特币购买的两个披萨，标价41美元。）

比特币凭什么能当钱花？“挖矿”是什么意思？比特币的未来在哪？ 这些问题的答案，都在于虚拟货币的核心技术——区块链。许多人一听到这种“故弄玄虚”的名词，就开始头疼。不要紧，今天我们“说人话”。

首先，区块链是用来记事的。但好好的U盘不用，为什么非要用区块链呢？

Blockchain is information storage that you can trust.

Unlike a disk or a USB drive, blockchain stores information that cannot be tampered with.

举个例子，你在和一个淘宝卖家讨价还价。为了防止有人反悔，你们把聊天记录保存成了区块链。

王小明（17:00:00）：“老哥给我打个八折好不好？”

淘宝JS（17:00:05）：“不行的亲，最多八五折。”

王小明（17:00:10）：“好的吧，我下单了。”

Let's pack this simple conversation into a simple blockchain. We are going to pack each sentence into a "block" and then link them into a "chain". First let's transform the three lines using a technique called “hashing.” In this example we use an algorithm called SHA1 to do the job.

从技术上讲，SHA1并不是加密算法，而是“哈希”（hash）算法。最大的不同之处在于，hash过的信息无法解密还原，只能用来“验明正身”——相同的信息，每次hash的结果也都是相同的。

三条聊天记录经过hash，就变成了这样三行“乱码”：

96cfa1c39f34e9ae9986a96292bfe8ee33c5b888

849f4be440cf555bb65d31bfa1407edbcb6ea123

d4a34fc0a0b080107d6944bf5eb7fe05945b2690

把这些信息串起来，一个简单的区块链就诞生了。

如图：

This blockchain will be stored in the computers of all Taobao users. If someone changed any bit of the conversation, the hash text will not be able to match with anyone else's. So the tampered conversation will not be trusted by anyone. This is basically how blockchain technology works to ensure the authenticity of the information.

The Bitcoin works roughly the same, except the information stored is not a conversation, but a ledger of Bitcoin transactions.

同样地，黑客无法把自己的比特币改多。因为每个人手上都有一份账本，改过的账本和大家对不上，那就不算数。这就是比特币号称“无需监管”的主要原因。

If you want more Bitcoin, you can use your computer to hash all the blocks in the chain again. The more hashing you do, the more you contribute to the Bitcoin’s integrity.

You get a reward for this contribution, which used to be 50 Bitcoins as mentioned by the pizza guy. That's what mining is all about.

除了比特币，区块链还有什么应用？

We at CGTN have reported that blockchain may be used to establish a better financial system, fight climate change or even stop poverty.

Simply search "blockchain" in our mobile app to find out more about our coverage on the topic.

Story by Gong Zhe