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Re: Problem with /dev/random?


Thanks for responding.

I am not logged in remotely but locally. I've had a "cat /dev/random"
running in a GNOME Terminal tab (window) now for several hours while I
read mail & surfed. It has printed nothing out. It has never printed
anything out, even at the very beginning.

I also moved the mouse for a good thirty seconds. Nothing.

So it appears to me that something else is wrong or improperly set up.
What happens when you cat /dev/random? Do you get some stuff out and
then periodicly as more entropy becomes available?

--- Vladimir

P.S. I thought I remembered reading that network traffic was added to
the entropy pool. Since I am listening to Internet radio, there are
always packets coming in.

Vladimir G. Ivanovic                        http://leonora.org/~vladimir
2770 Cowper St.                                         vladimir acm org
Palo Alto, CA 94306-2447                                 +1 650 678 8014
>>>>> "kb" == Kent Borg <kentborg borg org> writes:

    kb> On Thu, May 13, 2004 at 11:54:48AM -0700, Vladimir G. Ivanovic wrote:
    >> Well, I did as suggested. Nothing. 'cat' hangs:
    >> open("/dev/random", O_RDONLY|O_LARGEFILE) = 3
    >> fstat64(3, {st_mode=S_IFCHR|0644, st_rdev=makedev(1, 8), ...}) = 0
    >> read(3, 
    >> and never writes anything to the screen.
    >> How do I get GnuPG to generate keys? Do I have a problem with
    >> /dev/random? (/dev/urandom seems to work. It spits out garbage
    >> continuously when cat'ed.)
    kb> I can maybe help a little here.
    kb> /dev/random pulls random numbers from the kernel's entropy pool, and
    kb> if the kernel estimates that there is not enough entropy, it blocks
    kb> until there is enough entropy.  /dev/urandom also produces random
    kb> numbers but it doesn't block when the entropy estimation runs out.
    kb> Normally /dev/urandom is about as good as /dev/random, but NOT in your
    kb> case, because you seem to have no source of entropy.
    kb> The easiest and least controversial source of entropy for most
    kb> computers is the timing of mouse mouse movement.  The keyboard is also
    kb> good.  Less good is the timing of network packets or variation in disk
    kb> activity timings.  Keyboards and mice usually default to producing
    kb> entropy, I don't think other sources do.
    kb> In your case you seem to have no sources of entropy.  Are you logged
    kb> in remotely?  (If so, can someone wiggle the mouse?)
    kb> Off the top of my head, I don't know what you should do next.  I think
    kb> there is a way to enable entropy collection for a given device on a
    kb> live machine, but I don't remember how.
    kb> A related issue: On shutdown the system saves the entropy pool to
    kb> disk, and on startup it restores the entropy pool from disk.  This
    kb> means the very first time a new install boots, there is no entropy
    kb> until some hgas had a chance to build up from someplace.  At least in
    kb> RH 9 the system also creates some keys on the first boot--at a point
    kb> when there is no entropy!  (I forget which keys, I know I created
    kb> fresh ones on my box once I discovered that.)  Does Fedora have this
    kb> bug too?
    kb> -kb
    kb> -- 
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