Messages in this thread | | | Date | Mon, 19 May 2008 10:45:23 +0100 | From | Jeremy Fitzhardinge <> | Subject | Re: [PATCH 2/2] lguest: virtio-rng support |
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Rusty Russell wrote: > Unfortunately not. Hardware randomness devices export /dev/hwrng, and it's up > to userspace to feed that into /dev/random (or not). That's usually done by > rngd, which at least on my system, assumes 1 bit of entropy per bit of data > from /dev/hwrng by default. > > I was a little surprised that this decision was exported to userspace, but if > you're not prepared to unconditionally trust hw rngs, it makes sense to palm > it off.
Yeah, that's a bit of a pity. Hardware rngs can often generate really crappy randomness, which needs tons of processing to remove noise like 50/60hz hum, etc.
> We could write a boutique device for virtualization which *did* feed > directly, but that would be a little gauche. >
Well, yes, we can certainly do any amount of processing we like to the stuff provided to guests, so that the 1:1 bits/entropy ratio is as true as we can make it.
J
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