bobbyblue's blog

Securely deleting files and wiping your HDD

You have multiple files that you decide you want to get rid of. So, you right-click and select 'Delete' and then it's gone, right? Wrong. This is because files on your computer are accessed through a file allocation table, which tells the operating system where in your disk a file can be found. These are marked on the file allocation table by it's identifier. When you delete a file you are not really deleting it off your computer, but are instead simply removing it's entry on the file allocation table so that the computer can no longer access it.



The process securely removing information happens when you can remove it and write it over with bits of random data multiple times. However, it is difficult for the average uneducated computer user to differentiate between how many is not enough.

7 passes is the national standard for the U.S. government.

8 passes is the national standard for Canada's government.

Britian's national standard for overwritting files is 38.

The Gutman Method just not only overwrites data with 35 passes, but it does much more than that.There are a number of applications you can use to securely erase files, and yes, even your entire hard drive. The best option to erase files is a nice program called "Window Washer". With Window Washer you can select between Quick method(1 pass), DoD(7 passes), NSA(14 passes), Gutman(35 passes), and Random(you select your own number of passes manually). Window Washer also gives you the option of creating a bootable disk to wipe your HDD with the same methods listed above. However, I highly highly recommend something called "Darik's Boot and Nuke" or DBAN. This is a boot disk that gives you the passes mentioned above, while giving you different methods of magnetic wiping methods.