1. Data Recovery: Why Secure Deletion is so Important.
By: Jonathan Charlton
IASP 470 DLA

2. Is that file you deleted, really deleted?
When you click “Delete” on a file what happens to it?
When a file is deleted from your Recycling Bin the contents are not deleted.
Instead of deleting the contents, the route through which you access the file normally is just cut off until new data overwrites the sector that used to exist where the deleted file was present.
Why is this done?
If the contents were to be completely deleted it would require the processing power of writing the same file size you removed to the disk again.
For example, deleting a 1GB file takes the same time as creating a new 1GB file on top of the time to delete it.

3. So Do I Have to burn all my Drives?
While that is the most secure way to completely remove a file from existence, it is not entirely necessary.
While some individuals claim that complete destruction of a drive is required to erase the contents from existence, there are tools that will automate the process of clearing the space the deleted content was once stored.
Popular program CCleaner has a feature to completely wipe the “Free” space on your hard drive.
Wiping the “Free” space actually rewrites the space available for storing files on your drive with just 1’s and 0’s.
Once wiped the data in its entirety will be removed in most cases.

4. The SSD Issue
While hard drives may have a method of erasing the contents entirely, you cannot remove the contents of a Solid-State-Drive or USB in the same way.
The only completely secure method of deleting SSD contents or USB contents is destroying the drive that houses them.
Even two completely wipes of an SSD will still produce some of the data that was meant to be deleted, not always, but even once is too often when security is a concern.
So what can be done to secure your data?
Full-Disk-Encryption is the most common method of safely storing data on an SSD or USB flash drive.
Pictured on the right is a program for windows known as Recuva, it does an excellent job of recovering files that have been deleted without secure methods. Conveniently, Piriform the company that created Recuva, also created CCleaner.

5. Why Bother with Secure Deletion?
So why is it actually important that you securely remove files, your device shouldn’t leave your possession right?
Often systems are compromised without user knowledge, Remote Administration Tools or RATs allow an intruder full access to all of your system’s files and permissions.
A skilled hacker with administrative access to your PC can clone your system entirely without you ever knowing. Your files are now theirs, unencrypted and free to browse.
And even if you aren’t infected with a RAT, there are many other forms of malware that can achieve the same or similar results.

6. “I Don’t do Anything Bad I Have Nothing to Hide”
A common phrase associated with those who are less privacy driven than myself, but those who are not secure are at risk as well.
The “bad people” who know what they are doing is a problem are usually the most secure individuals because they don’t want to be caught.
The “good people” who don’t care about system security can be the scapegoat for the “bad people” much easier.
If I want to blame you for having an illegal image and I host it on your computer and delete it, you are now the owner of that illegal image and can be taken to jail for it.

7. “But I Didn’t Download that File”
You don’t even need to download a file for it to be on your computer, because your computer caches images it comes into contact with.
This was an issue, (and still is) with popular media-sharing application “Snapchat” that is meant to delete images after a few seconds once you receive them.
If you clicked on an image once, or viewed it in any way, a temporary version of it can be accessed without clicking “save”.
It isn’t just images your computer saves either, browser cookies hold an enormous amount of your personal data.
If you aren’t already, start clearing those cookies.

8. The Truth About Data Security Online
The hard fact about having any of your information or data on a device connected to the internet is, it is never completely safe.
Every day we hear about some new data breach in the real world, on targets that are by no means easy to infiltrate.
Our data is not completely in our hands anymore, everywhere you have entered data online, every account you have created and every interaction with a Federal establishment that required your information can be found online or in some database if it was stored.
This means you are always at risk and should account for that possible risk with a contingency plan at any given point in your life.

9. What I Want to Achieve With this Project
I want to gain and impart onto others a greater understanding of safe deletion methods for your data both online and offline.
I want anyone that views my project to at least be able to delete a file from their computer completely without having a way to recover it by any normal methods.
I want anyone that views my project to feel a greater sense of security through what they have learned and I want everyone to be able to add a program that I talk about to their own set of tools.