Data Remanence: Explanation and Removing the Residual Data
Data retention refers to leftover (magnetized) data that remains even after securely erasing data from your hard drives or USB sticks. Sometimes even formatting a disc does not delete entire data and leaves enough characters to reconstruct the data on that disc. Of course, someone trying to access the deleted data uses special software and hardware. In this article, we will see what data persistence is and how to eliminate it.
What is data persistence
When data is simply deleted using the Delete command from the context menu, it simply removes the address of the deleted file from the file allocation table. This data can be recovered using different data recovery software. This is why people want to erase all data securely with the help of specially designed secure removal software.
These data recovery software writes random data to deleted files. However, this software as well as formatting a disc still leaves data. These data bits can be recovered and the information can be reconstructed. This is why we need special software to completely erase deleted data from any type of magnetic storage.
In some cases, the head size of hard drives is different. It is therefore possible that when the magnetic storage is deleted, it can still be recovered using a different head size. The term “head” here designates the read / write head present in the hard disks and the tapes.
To safely erase data so that it cannot be reconstructed, there are certain tools which we will talk about in the sections below. For now, it is important to know that data cannot be completely deleted from any storage. So people use overwriting as a solution to make the remaining data unrecoverable.
How to completely delete the remaining data?
The term "Remnant" refers to everything (magnetism) that remains after deleting large pieces (of data on storage devices). There are a few good methods to eliminate data persistence:
- HDD Secure Erase Commands
- demagnetization
- Media destruction.
Please note that there are programs like CCleaner that talk about secure erasure of your data. They try to erase the data by overwriting the files to be deleted. That is to say, they write the 1s and 0s over and over again on the parts of the storage to be deleted, which makes recovery difficult. This does not completely delete the data and the remains will still be there.
If such hard drives and magnetic tapes are discarded or given to someone else, it is likely that the person who gets the drive or the "cleaned" tapes can still recover the bits to reconstruct the data that have been tempted to be cleaned.
1) Eliminate data persistence – Secure hard drive controls
Secure Erase is a set of command line commands that act on the firmware and therefore will not be able to communicate directly with the hard drive to be deleted. They can be used with third-party software in order for commands to be executed. There are third-party hard drive erasing tools that execute these commands to erase data securely. An example of such a tool is DBAN (Darik’s Boot and Nuke).
The Secure Erase data deletion method is implemented by writing 0 or 1 to the entire drive to be erased. You already know that computers use a binary language that has 0 or 1 as characters.
As previously stated, the Secure Erase data destruction commands cannot act directly on the hard drive even if you execute them using the elevated command prompt. You should use solutions that allow you to modify the firmware or that already have built-in tools to issue commands to the firmware.
Please note that Secure Erase HDD commands may not work on SSDs. If you need to delete an SSD, you must demagnetize it or physically destroy the entire SSD.
Another problem with the secure erase commands is that they cannot partially delete hard drives. They are only used when the entire hard drive needs to be cleaned before throwing it away or before giving the hard drive to a person / charity / schools, etc.
To clean up parts of hard drives such as files and folders, you can Download and use Eraser. He is able to suppress reminiscence
2) Disinfection of hard disks: demagnetization method
The term "demagnetization" refers to the removal of the magnetic field from magnetic storage drives: hard drives and tapes. When you degauss a magnetic disc player, you simply delete the marked tracks and sectors, making the disc unusable. It removes basic magnetism that contains data. Otherwise, the data is not readable because the file allocation table then does not know how to access the data still stored on the drive. And since it destroys the magnetic plates, it can no longer be reused.
3) Destruction of physical media to eliminate the persistence of data
In cases where it is too personal data on the drive or a security issue, the recommended method is to physically destroy the disc. Use something like a hammer to open the case. Then strike the magnetic plates to remove them from their compact case. Once exposed, each hard drive plate can be removed and burned. Do not throw hard drives into a fire without removing their cases. They can explode.
The above explains what data persistence is and how to eliminate it. I am sure there may be more methods to destroy these remains. If you know of one that I haven't covered, please share it with us in the comments below.