What if every page visited, every email sent, every chat logged could be retrieved by someone? Scary thought huh. Well you may not be doing something illegal, you may not have anything embarrassing or even have anything of high value someone could steal. But just the thought someone could retrieve all that information is a scary thought that most people do not even think about. This article is not meant to scare you or put you in fear of ever using the internet again. It is just a reminder and wake up call for those not aware that there are ways to recover all that data, for good or for bad.
“Computer forensics” is the actual term used for retrieval of data. If you just erase your email or file and think it is gone, you are wrong. Through ways of computer forensics and software it is possible to retrieve that data. Now if you go through a more elaborate way of erasing files like encryption, degaussing, overwriting or physical destruction, it is argued that it is impossible to retrieve data. You can count on the fact that your employee, family, school mate or a random person is not going to be able to retrieve that info. It is still debated whether or not the computer forensic experts & government agencies can or cannot retrieve the data through advanced techniques though.
If you want to delete data from your hard drive and still be able to use the computer, your best bet is software.
Software does this through what is called shredding or wiping a file. Pretty much it usually just overwrites the existing data with new data in different patterns. If you do this you have to be sure of what you are trying to erase, because after you overwrite data there is no way to get it back(assuming you do not work for the government and retrieval is really possible).
Encryption is another method which in most cases works well, but it is not full proof and still has the ability to get hacked and retrieved.
Degaussing is a method of removing a magnetic field of a hard drive or disk. This method works great, but at the same time ruins your hard drive so you cannot use it again.
Reformatting, reimaging or repartitioning a computer does not always overwrite every area of the drive, it may appear to be erase but some of the drive is still there and able to be retrieved.
So before you just throw or give that computer away, just remember that if you simply erase files it is not enough to permanently get rid of them. The best way if you are going to use your computer or pass it on is to use a software application to overwrite the data. If you are going to destroy a computer or do not care about it anymore, the best way is degaussing or physical destruction like incinerating, adding corrosive chemicals, physically breaking through shredding or grinding etc.
This all can be good or bad news depending on the purpose of your deletion or retrieval of information and hopefully you now have a better understanding of how computer forensics & data retrieval works and the steps needed to protect yourself.