[ubuntu-uk] Securely delete data

[Tyler J. Wagner]

I'm responding to both Andres and Alan, because my answers are related.

On 2012-11-17 21:02, Andres Muniz wrote:
> wow this shred stuff is really interesting. If i have EXT4 running on a
> solid state drive (ssd), does it mean that doing a shred will significantly
> reduce the life of the ssd?

It will reduce the life of the SSD by one write per block, per pass of shred.

On 2012-11-16 17:30, Alan Pope wrote:
> More passes don't really give you any benefit. A simple single run of dd
> is sufficient.

That depends against what you are trying to defend. It is possible, with
specialist tools, to recover data after a single wipe. This is especially
true when the wipe is done with uniform data, such as all zeros. So if you
want to prevent the next owner of a laptop from running photorec, one pass
is fine. If you want to stop a data recovery specialist or intelligence
agency, it is not.

And Andres, securely deleting SSDs requires another tool. I suggest reading
the following:

http://arstechnica.com/security/2011/03/ask-ars-how-can-i-safely-erase-the-data-from-my-ssd-drive/

http://www.unixmen.com/secure-erase-your-ssd/

http://howto.cnet.com/8301-11310_39-20115106-285/how-to-securely-erase-an-ssd-drive/

Regards,
Tyler


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