On 17 Dec 2009, at 13:40, Marcus Wanner wrote:
On 12/17/2009 6:42 AM, Mick wrote:
On Thursday 17 December 2009 05:13:32 Joshua Murphy wrote:
chicane ~ # shred test/
shred: test/: failed to open for writing: Is a directory
chicane ~ # shred -v -n 25 -z -u ~/test/
shred: /root/test/: failed to open for writing: Is a directory
shred ... shreds files. Therefore you may need to point it to the
files in
question for it to work. I suspect that if you point it to a
device alone it
just shreds the file representing the device on the Linux fs in
question.
That would be a bit inconvenient...I still vote for dd, overwriting
the thing 26 times sounds like WAY overkill for a hdd...
The US military specification is to overwrite randomly 3 times:
http://en.wikipedia.org/wiki/Data_erasure
I think the `shred` on the current System Rescue CD defaults to this.
The advice to overwrite 26-35 times is, I think, based on Peter
Gutmann's 1996 advice, which is now quite dated and is widely
considered no longer relevant. Fair play to Gutmann: there aren't many
studies on secure data removal made publicly available, so it was the
best knowledge we had at the time. It may be accurate to the kind of
drives available then, but not to those available now.
Why not use dd? Grant says that his data "isn't too sensitive", so it
doesn't really matter. But it's no more difficult to run shred than it
is to run `dd` - it's about the same amount of typing. You might as
well "do things properly" (also known as "following best practices"),
even if you don't think you need to. 3 writes really doesn't take that
long.
Stroller.
