[cryptography] Question on Entropy Gathering

Sandy Harris sandyinchina at gmail.com
Sun Mar 3 16:15:00 EST 2013


On Sun, Mar 3, 2013 at 3:30 PM, Jeffrey Walton <noloader at gmail.com> wrote:

> In Jesse Walker's slide on "Requirements for random number generators"
> (https://crypto.stanford.edu/RealWorldCrypto/slides/jesse.pdf), Walker
> provides a simple gatherer on slide 10:
>
> unsigned before, after, entropy;
> before = read_TSC();
> usleep(0);
> after = read_TSC();
> entropy = (after – before) & 0x0ff;
> Repeat until sufficient entropy harvested

One possibly relevant paper:
McGuire, Okech & Schiesser, Analysis of inherent randomness of the Linux kernel,
http://lwn.net/images/conf/rtlws11/random-hardware.pdf

My attempt at a generator based on such ideas:
ftp://ftp.cs.sjtu.edu.cn:990/sandy/maxwell/
> suitable on platforms with a high resolution counter? In this case,
> one would only need to call the correct Operating System function (for
> example, QueryPerformanceCounter()).
>
> Jeff
> _______________________________________________
> cryptography mailing list
> cryptography at randombit.net
> http://lists.randombit.net/mailman/listinfo/cryptography



More information about the cryptography mailing list