$ cat /proc/sys/kernel/random/entropy_avail
will give you current available entropy on the system. This number drops when you read from any of these devices(random/urandom).
Please refer : http://vinitsworld.blogspot.com/2008/10/difference-between-devrandom-and.html
-Vinit
On Fri, Aug 28, 2009 at 1:17 PM, loody <miloody@xxxxxxxxx> wrote:
Hi:
2009/8/28 Martin Møller Skarbiniks Pedersen <traxplayer@xxxxxxxxx>:
> 2009/8/28 loody <miloody@xxxxxxxxx>:
>> Dear all:> You can't except to read a lot of data from a /dev/random file
>> I made linux running on Mips machine.
>> Right now I found the /dev/random doesn't work properly, since I use
>> "dd if=/dev/random of=/tmp/random.txt", it stops working.
>> If I use "cat /dev/random", it will not pop out anything.
>>
>
> From the man-page:
>
> "
> When read, the /dev/random device will only return random bytes
> within the estimated number of bits of noise in the entropy pool.
> /dev/random should be suitable for uses that need very high quality
> randomness such as one-time pad or key generation.
> When the entropy pool is empty, reads from /dev/random will block
> until additional environmental noise is gathered.
> "
>
> Use /dev/urandom instead.
thanks for your kind help :)
after reading your suggestion, I guess maybe the problem comes my
environment noise.
Since the document says the /dev/random use environment noise to
generate random number.
How could I check my environment noise is enough?
appreciate your help,
miloody
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