Messages in this thread | | | Date | Fri, 4 Aug 2006 13:00:30 +0000 (GMT) | From | moreau francis <> | Subject | Re : [HW_RNG] How to use generic rng in kernel space |
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Michael Buesch wrote: > The dataflow is as follows:
> HW-RNG -> userspace RNGD (through /dev/hwrng) -> the daemon > checks it for sanity and puts it back into the kernel through > /dev/random -> Your driver gets the data from the /dev/random > entropy pools.
Is that also true for embedded systems ? I mean we may not found any rngd on these systems.
One other question now: suppose that others drivers need to use random data during their inits. At this time userspace appli still not have been started. How does it work ?
> This is very neccesary, because your HW-RNG may fail and > so you may unintentionally use non-random data, if you use > the random data from the RNG directly. > The data _must_ go through userspace rngd, which does FIPS > sanity checks on the data.
Well I'm working on a secure SOC which have a randown hardware which is supposed to return true random data. I understand that some self tests on the random data are needed but doing them in userspace is suprising.
thanks
Francis
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