On Sat 2013-11-02 12:01:12, Pavel Machek wrote: > Hi! > > > >sense of where the unpredictability might be coming from, and whether > > >the unpredictability is coming from something which is fundamentally > > >arising from something which is chaotic or quantum effect, or just > > >because we don't have a good way of modelling the behavior of the > > >L1/L2 cache (for example) and that is spoofing your entropy estimator. > > > > Please note: if the jitter really comes from the oscillator effect of > > the RAM clock vs. the CPU clock (which I suspect), we will not be able > > to alter the jitter software wise. > > Well... if it is really oscillator effect, there should be _no_ > entropy when running with L1/L2 enabled (because DRAM will not be > accessed at all at that case). > > There should be way to extract entropy more directly from various > oscillator effects, no? Actually... bogomips calibrating loop already has jitter, measured from difference between CPU clock and system clock... Could that be used as entropy source? As a bonus, we should have it on most platforms... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
