Securely delete files from your hard disk using Cipher

Normally, when you delete a file, only the file’s entry in the filesystem table is deleted; the actual data contained in the file remains in the folder until it is overwritten with another file. Cipher, a command line tool, allows you to securely wipe data, which means that is deletes the files and overwrites the leftover data with random bits.

This effectively makes it impossible to subsequently recover deleted data with an “undelete” utility. Think of the wipe feature as a virtual paper shredder. Interestingly enough, I wrote about a program called File Shredder a while back that lets your securely erase files on your computer.

To wipe a folder, open a Command Prompt window and type cipher /w: foldername, where foldername is the full path of any folder on the drive to wipe.

Although Cipher requires the path of a folder, it actually wipes all the free space on the drive. This means that the commands cipher /w:c:\Users\Kakashi and cipher /w:c:\Users\Naruto have exactly the same result.

The /w option is explained in the cipher’s help display:

Set up Cipher to wipe folders containing sensitive data at regular intervals (or when Windows starts) to automatically protect deleted data. Note that Cipher’s /w option does not harm existing data, nor does it affect any files currently stored in the Recycle Bin. It also works on unencrypted folders and encrypted folders alike.

Because cipher writes blocks of data to override the unused disk space, the whole process could take a few minutes to complete depending on the size of your folder and the speed of your disk.