Secure file deletion

Posted on 22/10/2009 by


Have you ever had a very secret file on your computer, which you didn’t want anyone to see so you deleted it?

It may still be there. Waiting to be recovered by the police, FBI or another hacker.

When you delete a file the data will still be left on your hard drive. The only thing that actually happens is that the Operating System removes the reference of the file from the file system table. The actual contents of the file can be recovered using special recovery software, for example Final Data (

It’s a bit like when you’ve written something on a paper and erased it using a rubber. The text is still there, and you can still read it if you want to. But if you write something new over the erased text, erase the new text and repeat this some times, the original text won’t be readable anymore.

The same procedure can be used on a hard drive. The file will be emptied, overwritten, emptied, overwritten over and over again until it’s safe to delete the file. The magnetically remains of the file will be covered by other data and the file will be (almost) impossible to restore.

If you don’t want to write your own application to overwrite files (or spend your time doing this manually), you can download an application which does it for you.

You can find this application at


Posted in: Softwarez