我在想我的熵水平可能很低？
$ cat /proc/sys/kernel/random/entropy_avail
我平均在 132-178 左右。池大小默认为 4096（顺便说一下，这是虚拟器上的容器）。
我也跑了：
$ cat /dev/urandom | rngtest -c 1000
并得到：
rngtest: starting FIPS tests...
rngtest: bits received from input: 20000032
rngtest: FIPS 140-2 successes: 999
rngtest: FIPS 140-2 failures: 1
rngtest: FIPS 140-2(2001-10-10) Monobit: 0
rngtest: FIPS 140-2(2001-10-10) Poker: 0
rngtest: FIPS 140-2(2001-10-10) Runs: 1
rngtest: FIPS 140-2(2001-10-10) Long run: 0
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=26.272; avg=628.845; max=19073.486)Mibits/s
rngtest: FIPS tests speed: (min=73.928; avg=108.740; max=130.640)Mibits/s
rngtest: Program …