I prepare the old systems before I give them away. This involves deleting all files and the operating system, and installing a new operating system once the hard drives have been formatted and I have made sure that the data on the drives is no longer recoverable.

Software like Hardwipe can be used to erase hard drives securely. Securely in this regard means that the data on the drive will be wiped so that it cannot be recovered anymore.

Hardwipe is only one of the programs for that specific task. Other suitable applications include Prevent Restore, Eraser or Blank and Secure to name a few. All have in common that they overwrite files, hard drives or unused disk space to render file recovery software useless.

When you first start Hardwipe, you are presented with the following interface.

Here you can select to wipe files or drives, clean free space or purge the Windows swapfile. The configuration options on the right side of the interface remain the same regardless of selection. You can change the method that is used to overwrite data. Available are quick wipes which overwrite the selected data once to the Gutmann algorithm which overwrites data 35 times. It is furthermore possible to change the speed control setting from automated to full speed or restricted.

A click on Wipe Files opens a file browser which can be used to select individual files or folders for secure deletion. It is possible to select multiple files or folders by holding down the Ctrl key during selection.

Wipe Drive on the other hand asks the user to select a drive or partition to erase all data on that hard drive permanently. Clean Space finally is used to delete all traces of previous files on a partition’s or hard drive’s free space. The Purge Swapfile option, even though listed, is not functional yet.

Hardwipe is a solid alternative for other tools that wipe hard disks and delete files securely under Windows. Tooltips would be handy to explain some options in the program interface that may not be clear immediately. The software integrates into the Windows Explorer context menu to securely delete files and folders directly from the default file manager.

Windows users can download the latest version of Hardwipe from the developer website. The program is compatible with 32-bit and 64-bit editions of the Microsoft Windows operating system.

So…when you know you have to get rid of a file, so that it can never be recovered, what do you do? Well, in Linux you have a number of options. One of those options is secure-delete. This tool is quite handy in that it can securely remove files, folders, and even securely clean free space on your drive. In this article I am going to show you how to install and use secure-delete.

Installation

Installation of secure-delete is easy. Since this tool is a command-line only tool, I will show you how to install it from the command line. Here are the steps.

1. Open up a terminal window.
2. Issue the command sudo apt-get install secure-delete.
3. Type your sudo password (that’s your user password, in case you weren’t aware) and hit Enter.
4. Allow the installation to complete.

You now have secure-delete installed on your machine and ready to start trashing those files and folders.

Deleting a file

Let’s say you have a file in your home directory (~/) called secret_stuff.txt. To delete this with secure-delete you would use the srm command (secure remove). To do that you would issue the command like so:

srm ~/secret_stuff.txt

That file is now VERY gone. Don’t expect the removal of he file to be as fast as it would with the rm command. Why does it take longer? When you issue the srm command on a file, secure-delete does the following:

1. 1 Pass with 0xff.
2. 5 Random passes.
3. 27 Passes with special values defined by Peter Gutmann (a leading cryptographer).
4. Rename the file to random value.
5. Truncate the new file.

Between each pass the file is also opened by O_SYNC mode and then an fsync() call is made.

Deleting a folder

Deleting a folder is as simple as deleting a file. Let’s say you have the folder ~/secret_stuff that needs to be deleted for good. To do this with srm you would use the -r (recursive) switch like so:

srm -r ~/secret_stuff

Depending upon the size and the amount of the directory contents, the deletion will take some time.

Clearing free space

If you have installed and re-installed OSes on your computer, you could very easily have residual files remaining in the free space of your current installation. You can ensure that space is free of any traces of files or folders with the command sfill. There are two things about this command you need to know: You have to have admin rights (so you have to use sudo) and you have to know the mount point of the free space. This command is very slow, so make sure you give it plenty of time to run. Let’s say you have a drive attached to your machine that has been used a number of times and is mounted to /media/external. To completely clean out  the free space on this drive you would issue the command:

sudo sfill /media/external

After some time the free space on that particular drive would be completely free of any trace of directories or files.

Final thoughts

Using the secure-delete tools is a sure-fire way to permanently and irrevocably remove data from a drive. This tool is so powerful even forensics teams would have trouble extracting data from the drive. Just make sure you use this tool with caution, so you do not securely delete files you actually want to keep!

There have been numerous cases in the news where people bought used hard disk and found confidential files on them using tools to recover deleted data. Enter Darik’s Boot and Nuke.

Darik’s Boot and Nuke (“DBAN”) is a self-contained boot floppy that securely wipes the hard disks of most computers. DBAN will automatically and completely delete the contents of any hard disk that it can detect, which makes it an appropriate utility for bulk or emergency data destruction.

The freeware offers different secure wipe methods, works among others with IDE, SATA, SCSI drives and fits on one tiny floppy disk.

Take a look at this great tool at dban.sourceforge.net

DBAN and Permanent Hard Drive Data Deletion

Have you ever wanted to completely erase all data on a hard disk? Surely, this is not something that you would want to do on your own operating system, but if you are going to sell and old hard drive or you have recently purchased a new one, you can understand the importance of having a clean drive. As most of you already know, erasing data on a hard drive or even killing the data with a single pass doesn’t remove all recoverable data. You see messages like “formatting this disk will erase all data” and you might think that this wipes the drive and no data remains. In reality, there is software that can recover the “erased” data quickly. You don’t even need software to do it, except you own operating system.

There is this interesting self-contained floppy which can be run from the boot preferences menu to erase all hard drive data. It is called Darik’s Boot and Nuke, or “DBAN” for short. All of us love the acronyms and DBAN sounds good. Should you require destruction of data quickly, whatever reason that may be, this bootable floppy will eradicate all data on a hard drive.

If you wish to download DBAN, be sure that you DO NOT RUN this software. Save it to a portable disk and use it only on machines with hard drives you want to completely and irreversibly erase. Label the DBAN boot disk in a way that you can understand so that you don’t get it mixed up with your Linux boot disks or other ISO disks.

To better understand everything about DBAN, go here . All your questions will be answered. Be sure to go through every page, every FAQ, etc. This way, you will understand that this is before you attempt to use it.

DBAN can be started from DOS. According to the designer, the best way to do this is to use the LOADLIN program. A link is provided on the DBAN site if you do not already have LOADLIN, in other words: a Linux boot loader. Normally, LOADLIN would not affect other DOS file systems. In this case, DBAN creates an exception. Copy the kernel.bzi and initrd.gz files from the DBAN floppy to a DOS file system and run this command line:
loadlin kernel.bzi initrd=initrd.gz root=/dev/ram0 init=/rc nuke= “dwipe”

You can find this same information on the site links provided above, should you wish to confirm that the information being provided here is accurate. This command should go in the AUTOEXEC.BAT file. If you change the forward-slash characters to back-slash characters, you will have created a situation where DBAN cannot return to DOS.

Perhaps it is a better idea to use Syslinux or GRUB and avoid any risks associated with the method described above. Starting from DOS is a good idea if you know what you are doing with DOS and LOADLIN.

The best thing to do is to go to the links provided here and learn everything you can about this floppy hard drive wiping friend. Get all of the points down, as all information is clearly provided. Enjoy your clean hard drives!