Performance of /dev/urandom and /dev/random

Mihir Pandya mihir.m.pandya at
Fri Sep 28 10:59:05 EDT 2012

Thanks, that helped.

>From what I've read so far, the capacity of my entropy pool is 4096 bytes
and it's current size is 155 bytes. I'm wondering if the size of the
entropy pool affects the speed of generating the random numbers because
instead of breaking when the entropy pool runs out of bytes, urandom will
read the entropy pool again and generate more random numbers. So a smaller
pool size would mean that the frequency of file re-reads is higher which
would make it slower?

If I wanna test this hypothesis, is there any convenient way for me to
manually alter the size of the entropy pool size? I'm really trying to
optimize the generation of the cyrptographically secure random numbers.

On Fri, Sep 28, 2012 at 6:09 AM, Mulyadi Santosa
<mulyadi.santosa at>wrote:

> Hi...
> On Fri, Sep 28, 2012 at 3:54 PM, Sannu K <sannumail4foss at> wrote:
> >
> >So urandom  will take more
> > time than /dev/random.
> it's the other way around....
> --
> regards,
> Mulyadi Santosa
> Freelance Linux trainer and consultant
> blog:
> training:

Mihir Pandya
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