In my previous article on PC Inspector File Recovery, I showed how easy it is to recover or “unerase” supposedly deleted files. Extra measures must be taken to completely erase a file.
Deleting data on the disk is just like scratching out an entry in the table of contents. Though it does not show in the table of contents, the chapter still exists. Until the pages of the chapter are torn out, it will still be there. When deleting a file, all the computer does is scratch out the entry in the file system index. It is still on the hard drive somewhere but it is just harder to find. The data will stay there until the computer overwrites it when it needs the space. Because of this, it is fairly easy to “unerase” deleted files.
Secure Delete
How then does one actually delete a file so that it is no longer recoverable? A function like this is usually not built into operating systems. So, a third-party program is necessary. There are many programs out there that will securely delete the file. The best one that I have used is SuperShredder from AnalogX.
SuperShredder is very minimalist. The file size is small. The installation is short and simple. The graphical user interface (GUI) is understandable. And the configuration is minimal (if even needed at all). This is the main Window for the program:
Ways to Completely Erase a File
It is really simple to delete a file. There are three ways to do this.
The first way is to just drag a file or files onto the window.
The second way is to press “Select File” on the main window and browse for the file(s).
The easiest way to do this is to enable the SendTo shortcut. Go to “Config” and click “Create SendTo Shortcut.”
This will allow you to delete via right-clicking the file. The only difference between the normal right-click delete is that the secure delete is located in the SendTo menu. This makes it possible to completely delete a file without even manually opening the program!
It is important to take into consideration that this method for completely erasing data is intended for individual files. Keep watching for my next article on completely wiping hard drives or partitions!
December 12th, 2005 at 1:00 pm
Just a note to mac users out there –
This comes built into mac OS X, at least in tiger (10.4), and possibly earlier versions.
Just put the files into the trash, and choose ‘Secure Empty Trash’ from the ‘Finder’ menu.
If you are deleting an entire drive, there is an even more secure version of this available from the Disk Utility.
January 13th, 2006 at 8:32 am
what I have nout found yet is a program that erases *already deleted* files. If, for instance, confidential documents are scanned, the scan software usually generates temporary files on the system volume (containing the confidential information) and deletes them automatically after the final picture file of the scanned document is finished (typically on an encrypted and/or external volume). These deleted temporary files could be undeleted and read, as they are not overwritten. To my knowledge, the only secure method to erase these remains of confidential data is to “erase free disk space”, which some programs can do, but this is very time consuming. What one would need for this case is a program which first undeletes all files which have been deleted in, say, the last few hours, and then erases them. Does anybody know if such a program exists?
June 2nd, 2006 at 1:43 am
I translated this article to Chinese and post it in my blog.
http://blog.sina.com.cn/u/46dac66f010003or
Is it OK?
If you wont agree, I’ll delete it.
Thanks.