33 论工作量证明的难度
中本聪在此讨论了随着更多矿工开始参与挖矿，工作量证明难度也随之增加 。
工作量证明的难度增加
中本聪，2010年2月5日，下午07:19:12
2009年12月30日，工作量证明难度首次被自动调整。
最低难度是32个零位，所以即便只有一个人在运行比特币的节点，难度也不会比这更低。去年大部分时间的难度都在最低水平下徘徊。12月30日突破了难度 ，调整后的算法更加困难。从那时起，每次调整后都变得更难。
自2月4日的调整后，难度从去年的1.34上升到1.82。这意味着同样的工作量只能生成相当于原来55°%的比特币了。
难度的调整与全网的总工作量成正比。如果节点数翻番，难度也会翻番，让总产出回归到目标收益率。
对于那些技术控，可以通过在debug.log中搜索“target：”查看工作量证明难度。搜索结果是256位无符号十六进制数，其SHA-256值必须小于能成功产生区块的值。该值每2016个区块后调整一次，时间上差不多是两周。这时debug.log中会输出 “Get Next-Work Required RETARGET” 的消息。
minimum 00000000tfff0000000000000000000000000000000000000000000000000000
30/12/2009 00000000d86a0000000000000000000000000000000000000000000000000000
11/01/2010 00000000c4280000000000000000000000000000000000000000000000000000
25/01/2010 00000000be710000000000000000000000000000000000000000000000000000
04/02/2010 000000008cc30000000000000000000000000000000000000000000000000000
14/02/2010 0000000065465700000000000000000000000000000000000000000000000000
24/02/2010 0000000043b3e500000000000000000000000000000000000000000000000000
08/03/2010 00000000387f6f00000000000000000000000000000000000000000000000000
21/03/2010 0000000038137500000000000000000000000000000000000000000000000000
01/04/2010 000000002a111500000000000000000000000000000000000000000000000000
12/04/2010 0000000020bca700000000000000000000000000000000000000000000000000
21 /04/2010 0000000016546f00000000000000000000000000000000000000000000000000
04/05/2010 0000000013ec5300000000000000000000000000000000000000000000000000
19/05/2010 00000000159c2400000000000000000000000000000000000000000000000000
29/05/2010 000000000f67c00000000000000000000000000000000000000000000000000
11/06/2010 000000000eba6400000000000000000000000000000000000000000000000000
24/06/2010 000000000d314200000000000000000000000000000000000000000000000000
06/07/2010 000000000ae49300000000000000000000000000000000000000000000000000
13/07/2010 0000000005a3f400000000000000000000000000000000000000000000000000
16/07/2010 000000000168fd00000000000000000000000000000000000000000000000000
27/07/2010 00000000010c5a00000000000000000000000000000000000000000000000000
05/08/2010 0000000000ba1800000000000000000000000000000000000000000000000000
15/08/2010 0000000000800e00000000000000000000000000000000000000000000000000
26/08/2010 0000000000692000000000000000000000000000000000000000000000000000
date, difficulty factor, % change
2009 1.00
30/12/2009 1.18 +18%
11/01/2010 1.31 +11%
25/01/2010 1.34 +2%
04/02/2010 1.82 +36%
14/02/2010 2.53 +39%
24/02/2010 3.78 +49%
08/03/2010 4.53 +20%
21/03/2010 4.57 +9%
01/04/2010 6.09 +33%
12/04/2010 7.82 +28%
21/04/2010 11.46 +47%
04/05/2010 12.85 +12%
19/05/2010 11.85 -8%
29/05/2010 16.62 +40%
11/06/2010 17.38 +5%
24/06/2010 19.41 +12%
06/07/2010 23.50 +21%
13/07/2010 45.38 +93%
16/07/2010 181.54 +300%
27/07/2010 244.21 ++35%
05/08/2010 352.17 +44%
15/08/2010 511.77 +45%
26/08/2010 623.39 +22%