On Mon, Jan 14, 2013 at 02:21:00PM +0200, Marko Kreen wrote:
> Note: reading from /dev/urandom does not affect /dev/random.
Reading from /dev/urandom drains the pool that serves /dev/random:
$ cat /proc/sys/kernel/random/entropy_avail
3596
$ dd iflag=nonblock bs=100 count=1 if=/dev/random of=/dev/null
1+0 records in
1+0 records out
100 bytes (100 B) copied, 0.000174798 s, 572 kB/s
$ cat /proc/sys/kernel/random/entropy_avail
2839
$ head -c10000000 /dev/urandom >/dev/null
$ cat /proc/sys/kernel/random/entropy_avail
212
$ dd iflag=nonblock bs=100 count=1 if=/dev/random of=/dev/null
0+1 records in
0+1 records out
38 bytes (38 B) copied, 0.000101439 s, 375 kB/s
