Re: [PATCH] API for true Random Number Generators to add entropy (2.6.11)

Jeff Garzik
2005-03-24T05:14:20Z

David McCullough wrote:
> Jivin Jeff Garzik lays it down ...
>
>>On Thu, Mar 24, 2005 at 02:27:08PM +1000, David McCullough wrote:
>>
>>>Hi all,
>>>
>>>Here is a small patch for 2.6.11 that adds a routine:
>>>
>>> add_true_randomness(__u32 *buf, int nwords);
>>>
>>>so that true random number generator device drivers can add a entropy
>>>to the system. Drivers that use this can be found in the latest release
>>>of ocf-linux, an asynchronous crypto implementation for linux based on
>>>the *BSD Cryptographic Framework.
>>>
>>> http://ocf-linux.sourceforge.net/
>>>
>>>Adding this can dramatically improve the performance of /dev/random on
>>>small embedded systems which do not generate much entropy.
>>
>>We've already had hardware RNG support for a while now.
>>
>>No kernel patching needed.
>
>
> Are you talking about /dev/hw_random ? If not then sorry I didn't see it :-(
>
> On a lot of the small systems I work on, /dev/random is completely
> unresponsive, and all the apps use /dev/random, not /dev/hw_random.
>
> Would you suggest making /dev/random point to /dev/hw_random then ?

All the apps are supposed to use /dev/random, so that's correct.

For Hardware RNGs, userspace rngd daemon obtains entropy, checks it
(mainly checking for hardware failures), and then stuffs entropy into
the kernel random device. http://sf.net/projects/gkernel/

On the "to do" list is making rngd directly generate entropy use
'xstore' on VIA CPUs, rather than going kernel -> userland -> kernel.

Also, there are other entropy daemons floating about. I think there is
one that obtains noise from an audio device.

Jeff