🚀 go-pugleaf

Centuries ago, Nostradamus foresaw when "Clemens" <metax@despammed.com> would write:
> dd if=urandom of=/dev/hdb
> dd if=random of=/dev/hdb
>
> I want to overwrite my harddisk with random gibberish.
> What are the effects if I use "urandom"?
> What are the effects if I use "random"?
>
> What would you adwise, what�s more reliable and secure?

/dev/random will block any time the "entropy pool" runs out of bits
that it considers random, and wait until it gets some more entropy.
It will take a HUGE amount of time to run on a sizable partition.

/dev/urandom does not block in that manner, and will simply use the
cipher feedback to rehash whatever is in the entropy pool.

I would suggest a _third_ possibility, namely that you set up your own
cryptographically-strong RNG (there's lots of them out there to choose
from), using it to generate data to use as "gibberish," periodically
grabbing a byte or two from /dev/urandom or /dev/random to make it
behave a bit more randomly.

In addition, I'd suggest running this process multiple times, as it is
reputed that Those TLA Agencies are still able to pull data off if you
have only written over the disk once.

Of course, if you're really _serious_ about making this secure, you'd
want to use thermite to burn up the disk, grind it to powder, and then
mix it with thermite again...
-- 
(concatenate 'string "cbbrowne" "@ntlug.org")
http://cbbrowne.com/info/
Time is the best teacher; Unfortunately it kills all its students.