难度
5 条名言。中文为本站译文，每条附日期与原文链接。
为抵消硬件速度的提升和人们随时间运行节点的兴趣变化，工作量证明的难度由一个滑动平均值决定，目标是每小时平均产生的区块数。如果区块生成过快，难度就会上调。
英文原文
To compensate for increasing hardware speed and varying interest in running nodes over time, the proof-of-work difficulty is determined by a moving average targeting an average number of blocks per hour. If they're generated too fast, the difficulty increases.
随着计算机越来越快、用于创造比特币的总算力不断增加，难度会按比例上调，以保持新币总产量恒定。因此，未来每一年将产生多少新比特币，事先就是已知的。
英文原文
As computers get faster and the total computing power applied to creating bitcoins increases, the difficulty increases proportionally to keep the total new production constant. Thus, it is known in advance how many new bitcoins will be created every year in the future.
区块之间的目标间隔大概是 10 分钟。每个区块都包含其创建时间。如果时间偏差超过 36 小时，其他节点就不会在它上面继续工作。如果过去 6×24×30 个区块的时间跨度不足 15 天，说明区块生成过快，工作量证明难度翻倍。每个人都用同样的链上数据做同样的计算，所以大家在链的同一环节都会得出同样的结果。
英文原文
The target time between blocks will probably be 10 minutes. Every block includes its creation time. If the time is off by more than 36 hours, other nodes won't work on it. If the timespan over the last 6*24*30 blocks is less than 15 days, blocks are being generated too fast and the proof-of-work difficulty doubles. Everyone does the same calculation with the same chain data, so they all get the same result at the same link in the chain.
没错，难度调整的目标是让全网平均每小时生成 6 个区块。你的区块成熟所需的时间始终在 20 小时左右。
英文原文
Right, the difficulty adjustment is trying to keep it so the network as a whole generates an average of 6 blocks per hour. The time for your block to mature will always be around 20 hours.
难度刚刚提高了 4 倍，所以你现在的成本是每枚比特币 0.02 美元。
英文原文
Difficulty just increased by 4 times, so now your cost is US$0.02/BTC.