Hi Emerick --
--- In "Emerick Rogul" <> wrote:
>
> Hello,
>
> I'm implementing a cryptographic algorithm on a TS-7200 board and I need to
> produce a rather large random value to seed my random number generator (a
> minimum of 1024 bits of random data). I was planning to read from
> /dev/random, but it blocks forever - I'm guessing because
> /proc/sys/kernel/random/entropy_avail contains no data.
Yep, /dev/random will block if it runs out of entropy.
>
> Should I expect /dev/random to work (if so, how do I get the board
Yes, it should work. You don't mention what kernel you are using, but there
was at least one 2.4 bug where the entropy was not being 'refilled' properly.
to produce more entropy)? Or should I just use /dev/urandom instead (which
seems to work, but is supposedly not as cryptographically random)?
There have been discussions over the years about how to refill the entropy
pool; Typically it's done by hooking interrupts from the keyboard and mouse
driver(s), neither of which see much or any traffic in embedded systems. At
one time most network drivers contributed to the entropy pool, but that was
changed by the paranoids in case the attackers gain control of your network(!).
I'm not sure of the current situation.
/dev/urandom should be fine, unless you work for the NSA. If you're still
worried about it, look into having the network or serial driver contribute to
the entropy pool.
regards, ..... Charlie
>
> Thanks in advance for any help with this,
>
> -Emerick Rogul
>
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