Messages in this thread | | | Date | Tue, 29 May 2007 14:14:56 +0000 | From | Pavel Machek <> | Subject | Re: Seeding /dev/random not working |
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Hi!
> > I have two embedded boards (one ARM, one PowerPC), running two > > different versions of 2.6. They have no hard drives, keyboards or > > mice. They each have a NIC, but I understand these make no > > contribution to the entropy pool. > > > > if [ -f $random_seed ]; then > > cat $random_seed >/dev/urandom # should seed the pool > > fi > > dd if=/dev/urandom of=$random_seed count=1 2>/dev/null # save some > > data from urandom for next boot > > > > I have rebooted my boards many times, and after each boot I read the > > contents of $random_seed. Whilst it does not happen every time, the > > contents of $random_seed are /often the same/. To give you a feel: > > rebooted 11 times, got a total of 3 different outputs. > > Ok, so this is telling me a couple of things. First of all, if you're > only getting three outputs, it means that you don't have any > peripherals feeding entropy into the system from the boot sequence. > Without any hard drives, keyboards or mice, and a NIC whose device > driver hasn't been configured to feed entropy, you're definitely > hosed.
Can we get at least time-of-boot from rtc clock to the pool? We really should not be getting identical outputs...
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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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