Actually still confused

Posted May 7, 2015 16:23 UTC (Thu) by itvirta (guest, #49997)
In reply to: Actually still confused by fandingo
Parent article: Random numbers from CPU execution time jitter

> (For example, `dd if=/dev/urandom of=/dev/sda` is a terrible misuse.
> Instead, use something like
> `openssl enc -aes128 -k "shred" < /dev/urandom > /dev/sda`.)

Doesn't that still read from urandom as much as the dd since urandom
is used as the input data?

Maybe you mean something like
openssl enc -aes128 -pass file:/dev/urandom < /dev/zero > /dev/sda

(Or even with the -nosalt flag added, because otherwise the
output always starts with the string "Salted__".)

The idea is good, however. I've used shred(1) for wiping disks, and
in random mode it uses urandom directly to get the randomness. It
makes it hideously slow. Perhaps someone(tm) should patch it to support
a faster generator or just make a smarter dedicated (simple-to-use) tool. :)