If you plan on retiring your computer and giving it away to a friend or selling it, it is wise to sanitize the data it contains first.
A hard drive formatting will not do much to guarantee that personal data can not be recovered, you will need specialist data wiping software to overwrite the whole of your hard disk with a random pattern to make sure that nobody can get their hands on banking details, compromising pictures, personal emails or business customer records.
Data that you thought you had deleted several years ago can still be recovered as long as it has not been overwritten by another file on top, when Windows deletes a file it simple makes it invisible from the user and marks it with a zero (computers use the binary language) to indicate that the zone of the disk where that file is located can be used again if needed, if that hard disk sector is never used, then the data is easy to recover as it is still there and in reality has never been deleted, just made invisible to the user.
Freeware to securely wipe whole hard disk
CBL Data Shredder is freeware and does an excellent job at securely erasing hard disk data, including wiping the operating system which can contain temporary files that could be recovered by someone malicious. CBL Data Shredder can also be used to wipe USB sticks, external hard drives and memory cards.
To prevent unintentional damage to the computer system running the CBL Data Shredder software, you will not be able to wipe the drive containing your current Windows installation, if you want to wipe your computer operating system then download CBL Data Shredder .iso and make a bootable CD.
If you only want to wipe specific data files, then you will need different data wiping software, CBL Data Shredder does not have the capability to shred single files.
CBL Data Shredder custom overwriting patterns
Secure wiping software CBL Data Shredder has an ample number of data overwriting patterns, from the well known United States Department of Defense Standard 5220.22-M used by US government agencies to sanitize hard disks containing top secret data, up to the paranoid time consuming Peter Gutmann’s Algorithm, which random algorithm makes 35 overwriting passes in total and is considered a total overkill by most computer forensic experts.
CBL Data Shredder allows you to use the Bruce Schneier’s Algorithm for data wiping, a random bit pattern that makes it extremely hard for an attacker to determine how the overwriting may have affected remnants of data around the edges of the track on the disk.
You can also use the Germany BSI Verschlusssachen-IT-Richtlinien (VSITR) Standard (a seven data wiping pass used by The German Federal Office for IT Security) and the Royal Canadian Mounted Police DSX Method used by departments of the Canadian Government, however this alone is not an approved method by the Canadian authorities for sanitizing classified information, current Canadian Government standards also require the physical destruction of the media to sanitize top secret data.
The CBL Data Shredder program allows what is commonly known as zeroing a hard drive which consists on writing the number zero all over the hard disk on every single part of it. This data wiping method is one of the quickest, if you are up against a low level opponent it should suffice to stop low level data recovery tools but otherwise you will be better off using one of the other choice of data wiping methods.
The CBL Data Shredder program allows you to use custom text to be used as a pattern to overwrite the data on the hard drive, and you can add a signature to the end of the hard disk sector too if you wish so, all of these custom patterns to sanitize a hard drive can be useful to use an Hex Editor after the hard disk has been overwritten and make sure that every single byte has been overwritten with the chosen pattern, if you zero out the hard drive, all the data you should see looking at the hard disk plates with the Hex editor is the number zero on it, anything else would be an indication of remnant data left behind.
Big corporations might also want to use a unique data wiping pattern to identify who has handled and securely erased that specific hard drive if later on it turns up somewhere it should not be.
Once CBL Data Shredder has finished wiping the hard disk a report file will be saved as “CblWipe.txt” in the root folder of the Windows boot partition.
Where to download CBL Data Shredder?
In order to download CBL Data Shredder you will need to visit CBL Data Recovery Technologies Inc. homepage and enter a valid email address where you will be sent the download link.