In simple terms, data wiping is the process of removing data from a digital medium. However, this definition is incomplete because data wiping is more than just shift+delete. While writing data on a physical drive, the metal platters inside the hard drive encode the data into binary 0’s and 1’s using a magnetic medium. This binary data leaves behind a trail which, with proper technique, can be exploited to retrieve even deleted data. Thus, effective data wiping is very crucial.
All these technical terms can seem a bit overwhelming. Thus, when Shekhar’s sister Megha asked him about data wiping, he explained the process to her in a simple language. Megha was in the final year of her school at that time and was preparing a project on data wiping for her computer science exam. When all the content over the internet failed to give her a clear picture of the concept, she approached her brother for help, who happened to be a computer engineer.
Shekhar took the example of a wall with spray-painted graffiti to explain to Megha that even if the paint is cleansed off after a week or so, it will leave behind a clean space on the wall that is devoid of any dirt or grime. Though the colours will be gone, the clean space will spell the graffiti’s message loud and clear.
Shekhar also drew an analogy with this example and explained to his sister that the modern computing systems don’t really delete data, in spite of promising to do so. Instead, they look up for the start and end points of the data we want to delete and remove it in chunks, thus allowing us to rewrite over it again. This data, just like the clear space beneath the colours of the graffiti on the wall, lurk somewhere in our computer and can be retrieved using proper tools.
Now, as things got clearer, Megha asked Shekhar how permanent data wiping works? With a smile, Shekhar thought of explaining Megha with the example of the wall graffiti. He asked her what is more important; getting rid of the graffiti paint or removing the message reflected by the graffiti? After scratching her head for a few moments, Megha replied that deleting the graffiti’s message forever is of utmost importance.
Shekhar appreciated Megha’s smartness and then went on with his explanation. He said that this could be done by giving a fresh coat of paint over a section of the graffiti and leaving it to dry completely. He further added that when the new paint is washed off along with the graffiti beneath it, the wall would be left with a clear space without the grafitti’s message.
Now, Megha’s eyes sparkled as the idea of how data wiping works got clear in her head. Meanwhile, Shekhar approached towards a conclusion and declared that data wiping not only permanently removes the data from the computer but also removes the record of such data having ever existed.
Megha further wanted to know how binary data could be erased permanently. Shekhar felt proud about his sister asking the right question at the right time. He told Megha that in case of binary data, the sum total of 0’s and 1’s are blanked multiple times to delete the data permanently. All the data to be deleted is then replaced by straight 0’s and straight 1’s over and over again, thereby clearing any history of the existence of previous data.
Megha thanked Shekhar for his helpful insights on data wiping and headed over to her room to finish her project. She even decided to use Shekhar’s example of wall graffiti to make her project more interesting and subsequently scored high in her project.