Le dimanche 19 octobre 2014 à 11:37 -0700, Patrick O'Leary a écrit :
> On Sunday, October 19, 2014 12:55:08 PM UTC-5, Milan Bouchet-Valat
> wrote:
>         Le dimanche 19 octobre 2014 à 13:14 -0400, Stefan Karpinski a
>         écrit : 
>         > That might be why Python has a special function for reading
>         from it – 
>         > specialized caching behavior. 
>         Note that for those on bleeding-edge Linux distributions, a
>         new system 
>         call has just been added in 3.17 to get random numbers: 
>         http://lwn.net/Articles/606141/ 
>         
>         But my understanding is that for scientific applications (as
>         opposed to 
>         cryptographic ones), /dev/urandom isn't the best choice since
>         reading 
>         from it is quite expensive for the system due to security
>         requirements, 
>         and it costs entropy for programs which may really need it.
> 
> It uses a CSPRNG rather than non-CS PRNG, so it is more expensive, and
> unnecessarily so if you're not doing crypto. But I don't think the
> latter assertion is true--as long as enough entropy got into the pool
> in the first place, and no one is trying to use /dev/random (which
> they shouldn't be; see for instance
> http://www.2uo.de/myths-about-urandom/).
I guess you're right: that will only affect people using /dev/random.
But (even if that's useless), it's apparently the case of some programs,
like GnuPG when generating a key (admittedly not a very common
operation).


Regards

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