batch mode lack of randomness FreeBSD

Werner Koch wk at gnupg.org
Tue Mar 21 15:52:19 CET 2006


On Thu, 16 Mar 2006 01:10:25 -0500 (EST), Stef Caunter said:

> I've started a child process that continually writes to a disk file during 
> the --gen-key --batch job...

That won't help much.  A better thing is 

 find /usr -type f | xargs cat >dev/null

> Is this just the way it is on FreeBSD (4.11-RELEASE)? There is plenty of 
> randomness in /dev/urandom, and none in /dev/random...

There is no randomness (well, entropy) in /dev/urandom at all if you
read too much of it.  Instead of blocking on low entropy as
/dev/random does, /dev/uranmdom simply falls back into a pseudo random
mode.  Further, reading from /dev/urandom depletes the inetranl random
pool and thus a read on /dev/random will block untilo you stop using
/dev/urandom.


Salam-Shalom,

   Werner




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