Re: [RFC] [DISCUSSION] Reliable user-land CSPRNG

On Tue, Feb 24, 2015 at 1:39 PM, Leigh <leight@gmail.com> wrote: > On 24 February 2015 at 20:54, Pierre Joye <pierre.php@gmail.com> wrote: >> On Feb 24, 2015 12:04 PM, "Anthony Ferrara" <ircmaxell@gmail.com> wrote: >>> PERHAPS, it could be written in such a way that a PECL extension can >>> alter the RNG to accommodate that usecase. But I'd be wary of that and >>> core supporting userland RNGs. >> >> Yes, driver based. That brings some risk but worth exploring this >> possibility. > > We can make the function a pointer. That's not a problem. The problem > is when people assign their own function to this pointer :) > >> You actually reduce the data set, bytes level or higher, the randomness of >> the data is then restricted or limited and sequences may happen, worst case >> it could make it less hard (or easier) to predict. I have seen these cases >> in a couple of projects which rely heavily on entropy. > > If you need very high quality and high throughput entropy I can add > that to this patch. I left it out for now, because I didn't want this > to become over-complicated. If not having an fd-less crypto-quality > high throughput is a show stopper for you then let me know, we can fix > this. It is only about the amount of data. The trend to have bunch amount of apps running on the same physical host, it can exhaust the entropy quickly.