2. Transactions
We define an electronic coin as a chain of digital signatures. Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner and adding these to the end of the coin. A payee can verify the signatures to verify the chain of ownership.
The problem of course is the payee can't verify that one of the owners did not double-spend the coin. A common solution is to introduce a trusted central authority, or mint, that checks every transaction for double spending. After each transaction, the coin must be returned to the mint to issue a new coin, and only coins issued directly from the mint are trusted not to be double-spent. The problem with this solution is that the fate of the entire money system depends on the company running the mint, with every transaction having to go through them, just like a bank.
We need a way for the payee to know that the previous owners did not sign any earlier transactions. For our purposes, the earliest transaction is the one that counts, so we don't care about later attempts to double-spend. The only way to confirm the absence of a transaction is to be aware of all transactions. In the mint based model, the mint was aware of all transactions and decided which arrived first. To accomplish this without a trusted party, transactions must be publicly announced [1], and we need a system for participants to agree on a single history of the order in which they were received. The payee needs proof that at the time of each transaction, the majority of nodes agreed it was the first received.
第一段第一句（第一句）
We define an electronic coin as a chain of digital signatures.
我们把一种电子现金定义为一连串的数字签名。
第一段第二句（第二句）
Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner and adding these to the end of the coin.
每一位所有者通过对前一次交易和下一位拥有者的公钥签署一个随机散列的数字签名，并将这个签名附加在这枚电子货币的末尾，电子货币就发送给了下一位所有者。
第一段第三句（第三句）
A payee can verify the signatures to verify the chain of ownership.
收款人通过对签名进行检验，就能够验证该链条的所有者。
第一段小结
We define an electronic coin as a chain of digital signatures.
把电子货币定义为“一串数字签名”
Hash （哈希算法）
Payee:收款人
Owner：付款人（它是货币在转账前的拥有者）
第二段第一句（第四句）
The problem of course is the payee can't verify that one of the owners did not double-spend the coin.
这个过程的问题是收款人是否进行过双重支付没法验证
第二段第二句（第五句）
A common solution is to introduce a trusted central authority, or mint, that checks every transaction for double spending.
传统的做法是引入第三方或者每一笔交易都进行检查
第二段第三句（第六句）
After each transaction, the coin must be returned to the mint to issue a new coin, and only coins issued directly from the mint are trusted not to be double-spent.
每一笔交易之后，这个现金都要送回铸币厂发行新的币，只有从铸币厂新发行的币不能双重支付
第二段第四句（第七句）
The problem with this solution is that the fate of the entire money system depends on the company running the mint, with every transaction having to go through them, just like a bank.
这个解决方案的问题是这个货币体系的命运完全依赖于铸币厂了。因为每一笔交易都要经过该造币厂的确认，而该造币厂就好比是一家银行。
第三段第一句（第八句）
We need a way for the payee to know that the previous owners did not sign any earlier transactions.
我们需要收款人有某种方法，能够确保之前的所有者没有对更早发生的交易实施签名。
第三段第二句（第九句）
For our purposes, the earliest transaction is the one that counts, so we don't care about later attempts to double-spend.
对于我们来讲，我们只在乎最早的交易是真正作数的，而不关心转出后是否双重支付。
第三段第三句（第十句）
The only way to confirm the absence of a transaction is to be aware of all transactions.
确认某一个交易是否发生过只要知道所有的交易。
第三段第四句（第十一句）
In the mint based model, the mint was aware of all transactions and decided which arrived first.
在铸币厂模型中，铸币厂知道所有的交易，并且知道哪一个是第一个到的。
第三段第五句（第十二句）
To accomplish this without a trusted party, transactions must be publicly announced [1], and we need a system for participants to agree on a single history of the order in which they were received.
没有第三方要达到信任就得公开发布。我们需要整个系统内的所有参与者，都有唯一公认
的历史交易序列。
第三段第六句（第十三句）
The payee needs proof that at the time of each transaction, the majority of nodes agreed it was the first received.
收款人需要确保在交易期间绝大多数的节点都认同该交易是首次出现。
第十二句与第十三句：
要解决双重支付，我们需要一个公开的账本；同时这个账本需要一个系统，可保证每个参与者接受到的账本是一致的。
第三段小结：
用一个人人参与的网络代替银行的职能。
