Random number generators

Pedro Giffuni pfg at FreeBSD.org
Tue Mar 17 18:12:42 UTC 2015

Hi Dennis;

On 03/17/15 12:22, Dennis E. Hamilton wrote:
> There is a lot of discussion about qualities of Random Number generators on cryptography lists.  MT is not a good choice for that, but it might not need to be important for other applications.
> There has been some recent work, PCG, that has attracted some attention, <http://www.pcg-random.org/>.  There are good videos explaining what the approach is about as well.  PCG also has implementations in C.  (It is under the Apache License 2.0 too: <https://github.com/imneme/pcg-c-basic> for a minimal family and <https://github.com/imneme/pcg-c> for ones with extended capabilities.)
> The analysis of what does and doesn't work, and how passing diehard is too easy, is also valuable.
> If you are serious about crypto grade randomness, libc is probably not the answer.  Generally, I don't think reliance on a single generator for general purpose use and for cryptographic quality is going to work well.  This is a very context-sensitive situation and addressing specific threat models against cryptographic PRGs is a very different matter from wanting unpredictable and good quality pseudo-randoms for simulations and other purposes.

The pcg-random link seems to be down now but for crypto, we have 
arc4random(3) which is pretty good and about to be improved further.


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