Apr 20

Secure delete/shred files and wipe your hard drive to protect your personal data

Do you shred files with a secure delete or wipe your hard drive securely before disposing of it?

Unsurprisingly an extremely large portion of computer users  would answer no to this question leaving themselves open to a range of security issues from identity theft to personal and sensitive data theft.The number of times I have bought computers, laptops and hard drives from places like EBay or people have given to me to dispose of them without first running a secure delete of there files is amazing.

We are all in the habit (or should be) of disposing of things like bank statements by shredding them but we are not so diligent when it comes to disposing of our computers and their components and running a secure delete on our data. You only have to think about what is stored on the computer you are using now to realise how much of a security concern this is.

The problem is that whatever software method you use if someone wants to recover the data badly enough then there will always be a way. Having said that this is something only a handful of people can do with forensic software and very powerful computers (such as the police) and a secure delete for most people is unrecoverable. Mr Thomas down the road who is buying your computer for £100 is unlikely to have such equipment or the inclination but we still don’t want him been able to recover your personal details.

wipe hard drive imageDeleted does not mean gone!

When we delete a file or folder on our computer it goes into the recycle bin and we are led into a false sense of security believing that the file is gone forever. That is not the case and usless you have performed a secure delete on the file the only part that has been deleted is the header or index of the file.

You computer has deleted the header and been told that the space where the file was is now free and available.The only way this data is gone is if it is overwritten by some other data or via a secure delete of the file.Think of it like a library and removing a book from the index but not the book.You don’t remember to remove and destroy the unwanted  book until you put a new one in its place on the shelf even though you have removed it from your index system.The operating system will eventually overwrite this data but it could be at anytime meaning that information is recoverable using the right software.

How to secure delete your data

The first thing to check before performing any of these operations is that the data on your hard drive is definitely no longer needed.

One of the ways to securely delete data is to use a program that overwrites the data as well as removing the indexes (pointers) This makes the data pretty much impossible to recover but depending on the number of times you want to overwrite the data it can take some time tosecure delete the files(the more times the data is overwritten the more secure and less chance of recovery there is)

One such free program that can do this job is File shredder which can be download from


Another option is a program called Darik`s Boot and Nuke.

Darik’s Boot and Nuke (“DBAN”) is a self-contained boot disk 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. DBAN is a means of ensuring due diligence in computer recycling, a way of preventing identity theft if you want to sell a computer, and a good way to totally clean a Microsoft Windows installation of viruses and spyware.

This can be freely downloaded from http://www.dban.org This software needs to be burnt to a CD or DVD before it can be used.

Securely Destroying your hard drive

While a secure delete is one way of ensuring your files are not recovered you may not want to go through all of that so the other option is to destroy your hard drive.

There are many ways to destroy your hard drive if you are not selling it on. You still want to be sure that someone can’t recover your data so your best option here is to physically destroy your hard drive.

Pop the hard drive out of the computer and destroy it any way you can. My favourite option what I tend to use on a customer’s drive once I have replaced it is to get an old drill bit and drill numerous holes straight through the drive rendering it pretty much useless. This is quick and easy but can mean you need a new drill bit every time!

If you want to be a little more delicate and sophisticated or just want to see what is inside a hard drive you no longer want to use you could take the drive apart and destroy the hard drive platters where the data is stored.

So you have 2 choices. Secure delete your data or physically destroy your drive both will ensure that data recovery is unlikely

Related post: How to destory a hard drive 8 fun ways