RNG (was: Re: SSD drives)

[Amos Shapira]

If someone is really concerned about NSA knowing their random seed through
Intel's hardware implementation - can't these few people add hardware RNG's
to their sources?
(one ref:
http://en.wikipedia.org/wiki/Comparison_of_hardware_random_number_generators
)


On 3 January 2013 11:42, Oleg Goldshmidt <pub at goldshmidt.org> wrote:

> On Thu, Jan 3, 2013 at 1:50 PM, Nadav Har'El <nyh at math.technion.ac.il>
> wrote:
> > On Thu, Jan 03, 2013, Yedidyah Bar-David wrote about "RNG (was: Re: SSD
> drives)":
> >> RDRAND is also a PRNG, reseeded at most once every 1022 calls, way
> >> faster than /dev/urandom (they state 500MiB per second), and you do not
> >> have its source code...
> >
> > Can anyone give me an example of why on earth anyone would need a
> > very high throughput random number generator?
> >
> > I can understand why things like monte-carlo simulations and ray tracing
> > might need a lot of random numbers, but for them PRNG in the program
> > (e.g., rand(3)) is perfectly fine
>
> It is absolutely lousy for any serious simulation work - it is
> absolutely not random, and I know for a fact that in a serious Monte
> Carlo it will give you wrong results where a good PRNG will give you
> correct ones. In the past I tested many PRNGs on problems I knew the
> answer for. The vast majority were rubbish. Those that were very
> random (it was before NIST, so I relied on DIEHARD) gave good results.
>
> Actually, what is needed for simulations is uniform coverage of the
> state space, not randomness, which is why low-discrepancy (a.k.a.
> quasi-random) numbers work. Lousy PRNGs are not uniformly distributed
> (when you plot them the problem can often be seen by the naked eye).
> It leads to both lousy simulation results and weak cryptographic
> properties. Suitability for simulations does not mean strong
> cryptography.
>
> > for any of these super-duper super-secure generators in the kernel or
> the CPU...
>
> It has to be very random. It has been demonstrated many times how easy
> it is to exploit a not very random kernel RNG (guess TCP sequence
> numbers and so on). Microsoft: looking at you.
>
> --
> Oleg Goldshmidt | pub at goldshmidt.org
>
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