Re: Encrypting an External HDD

[Reco <recoverym4n@gmail.com>]

 Hi.

On Fri, 17 Apr 2015 12:08:31 -0700
David Christensen <dpchrist@holgerdanske.com> wrote:

> 1.  I use 'shred' when I want to fill a disk or partition with random 
> numbers.  It is ~1.7 orders of magnitude faster than /etc/urandom.

And 'shred' uses /dev/urandom in turn:

$ strace -e trace=file shred -s 100M - > /dev/null
…
open("/usr/lib/locale/locale-archive", O_RDONLY) = 3
open("/dev/urandom", O_RDONLY)          = 3

Although, according to strace, 'shred' cheats and only reads 2k bytes
from /dev/urandom, and not 100m as 'dd' does.

Given that, no wonder that shred is faster.

 
> 2.  Perl's Math::Random::ISAAC::XS is only slightly faster than 
> /dev/urandom.

That Perl module doesn't seem to use kernel-based entropy at all. Thank
you for pointing me out at it, now I know it so I avoid it.

Reco