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add some simple security

March 12, 2007

Just the sound of ‘computer security’ is often enough to intimidate the average pc user from even bothering…. it just sounds too complicated. But its not to hard to give yourself a little peace of mind on Ubuntu. By simply adding this feature to your file manager (nautilus) you can simply right click and “shred” the document instead of choosing the usual “move to trash”. shred.png


You wouldn’t dump private financial records out in the street trashbin without first shredding them, but far too often people will leave rather private documents sitting in a “trashbin” on a computer with several users. Even after the files are finally “deleted”, they still largely remain recorded on the hard drive for some time, possibly years after they were supposedly erased. Eventually many of those same well used computers are then sold, dumped, or donated to be further used by unknown people and potentially snooping criminals.


Choosing to shred the file instead of moving it to the trash is a much safer option for files that you’d regret falling into the wrong hands. Here’s how the author explains it:


This action uses the “shred” command to delete a file and make it unrecoverable. It overwrites 10 times and then overwrites with all zeros to hide the shredded file.

Installation Instructions:


In synaptic or terminal install “nautilus-actions”:


$ sudo apt-get install nautilus-actions

Then download the File Shredder script . Go to the menu System–>Preferences–>Nautilus Actions Configuration. Click import and select the shred.schemas file.


A Cautionary Note:


While although this simple tools is helpful, and much better than ‘move to trash’, it is most likely not a 100% secure method of data removal. Note that the man page for shred, has a caution warning that journaled file systems like ext3 render this less effective. You can read further debate about this issue in this thread on Ubuntu forums. Also, the SecuriTeam website has instructions to demonstrate the insecurity of shred. You may wish to read further information about ‘secure erase’ on this page from Stanford University.

Some linux alternatives to shred which may be more, less or similarly successful include fwipe, ya-wipe, and srm. 

Ideally a harddrive should be totally ‘wiped’ clean before being passed on to strangers. A topic for another day…

One Comment leave one →
  1. file systems question permalink
    August 10, 2008 9:33 pm

    looking through the manual for shred, it appears as though it will not work on “journaling file systems.” does anyone know if ubuntu 8.04 uses such a thing? (Ext3, XFS, Re3iser FS or JFS)

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