区块链入门

1. Definition of a Blockchain

A Blockchain is a constantly growing ledger that keeps a permanent record of all the transactions that have taken place, in a secure, chronological and immutable way.

For starters, a blockchain is a ledger(总账). It's a file that's constantly growing. So it keeps track of all the transactions, in a permanent way, which means once a transaction goes in, you can't pull it out. It's permanently in there. That information is placed in there in a secure way. It uses very advanced cryptography(加密) to make sure that it's actually locked inside the blockchain. The process, every transaction, gets placed in chronologically(按时间顺序) so every transaction that happens, happens after the previous one. And finally, it's all immutable(一成不变的) which means as you build that all these transactions onto the blockchain, this ledger can never be changed.

2. How Bitcoin works
   当我们用邮件发送照片的时候，我们实际上有two copies of the photo, 一个是邮件发送过去的，另一个original file还在我们电脑里面。What I really did was e-mail a copy of the file with the photo, not the original file. This issue is commonly known as the double-spend problem, and why we currently have a need for banks and other types of institutions to act as middlemen in these types of transactions.
   Without these intermediaries, people could simply try to copy and paste money and it would be impossible to determine if the transaction is real or not.
   所以double spend带来了一些列的挑战，那么如何能够在不需要银行，或者其他机构来证明你通过网络发给对方的钱的交易是真实存在的？
   The answer lies in a global network of thousands of computers called the Bitcoin network and a special type of de-centralized(分散的) ledger technology called blockchain. Blockchain is one of the key technologies that underlies Bitcoin, as it keeps a decentralized record of all the transactions that have ever taken place on the Bitcoin network. All the information is captured securely by using math and cryptography to protect it, and the data is stored and verified across the entire network of computers.
   换句话说，比特币在分散的计算机网络中用区块链技术，来安全地确认和记录每一个交易，而不是像用银行等第三方机构来确认这个交易的存在。 Because the data is stored in a decentralized manner across a wide network instead of a centralized database, there is no single point of failure. 这就使得存在区块链中的记录更加安全，更不容易被欺骗，篡改，或者是a general system failure than keeping them in a single centralized location.
3. 比特币矿工实际解决的是solving math problems and resolving cryptography issues, because every one of these transactions needs to be cryptographically encoded and secured. 而这些数学问题是能够确保没有人篡改这些信息的。
   比特币跟传统货币不一样the way that Bitcoin is created, is by rewarding these miners for their work in solving these math and cryptography problems.
   矿工的价值在于build the blockchain of records that form the Bitcoin ledger. And these are blocks and each block contains all the different transactions that have taken place. New blocks are added every 10 minutes to all the new transactions. So as the miners are processing these different transactions, they build a block, and when a block is confirmed, it gets added to the blockchain. This blockchain is built all the way back to the initial transaction ever in Bitcoin, which is regarded as the Genesis block.