How to do a secure data deletion on your hard disk
The reasons for requesting secure deletion can be various, the main one being to ensure that the data is no longer recoverable. This solution is mostly useful with disused hard disks or hard disks that are sold to others, to guarantee their subsequent safe use, in full respect of privacy and data security.
The safest method for permanent deletion is to overwrite the data.
Overwriting is the process by which new writes, and therefore new files inserted into any memory, overwrite the deleted files that are no longer visible to the user.
When one file is overwritten by another, only then it is really deleted so no data recovery program, even professional, can perceive valid or usable traces or fragments.
This is why this type of secure file deletion solution is suitable for situations in which you give your hard drive to other users, when it is regenerated and sold, or archived for disposal. By observing professional procedures for secure data deletion, the definitive deletion of files is ensured, as well as respect for data security and user privacy.
First of all, let's focus on the concept of "secure erasing", which is very different from the standard erasure to which most users are accustomed to, in terms of start-up model and the obtained result. If we need to proceed with a secure deletion, we assume that we prioritize the need to permanently delete the data, so that there is no trace of them, exactly as if the data (that we are going to securely erase) was never there in the first place.
Before examining the methods of secure data erasure, we're going to provide some mandatory clarifications about the differences between secure deletion and standard deletion.
Deleting data from a hard disk, a smartphone, or a pen drive, safely means ensuring that the data cannot subsequently be recovered in any way, shape or form.
When you delete the data with a standard deletion, actually, (even removing them from the Recycle Bin), they remain on our memories, and are hidden only from our view and from a "standard" search.
When we delete one of our files, we move it to the trash; then proceeding with the "Empty Trash" operation we think we can permanently remove it, but this is not the case at all: the file ends up in a part of memory that is perceived by the operating system as space available for new writes.
This is equivalent to saying that the deleted file is, therefore, ready to be overwritten. As long as the file is not overwritten it can be recovered with specific data recovery software for deleted files.
Once overwritten, the file is permanently lost. Standard deletion, by "Delete" or by formatting does not provide for secure removal of files from our memories. If our goal is to delete the data securely and definitively, we must proceed according to very different operations.
Our ChallengerOS operating system adopts ,as a secure deletion system, the file eresure by overwriting with the Rocket system.
With the Drive Secure Erase command inside Rocket, we start a definitive deletion of the data, which does not compromise the operation of the drive on which the procedure is started, but the latter is recertified as new, completely virgin, and free of any trace of the previous usage.
Following this safe erasing procedure, the hard disk is really ready to be disposed of, sold to third parties, or destined for any other use that has nothing to do with the previous one. No method of secure deletion can be considered as effective as the secure deletion of files by overwriting them.
Secure erase is a process which aims to overwrite all sectors on a block device with fixed or random patterns in one or several passes to destroy all data located on sectors.
When a block device sector data is overwritten by a secure erase process data will not be recoverable. Secure erase tasks will not damage device but only the data located on sectors.
Challenger Rocket offers several Secure erase methods with customizable patterns and secure erase schemes.
Secure Erase 0x00
Secure Erase 0x00 is a single pass overwrite method with no verify process with
zero bytes pattern.This is the fastest secure erase method.
Secure Erase Random + VERIFY
Secure Erase Random + VERIFY is a single pass overwrite method with random block pattern and verify command
NIST SP-800-88
Secure Erase NIST SP-800-88 is a National Institute of Standards and Technology secure erase standard. NIST SP-800-88 is a single pass sector overwrite process with no verify.
NAVSO P-5239-26
Secure Erase NAVSO P-5239-26 is a Standard US Navy Secure Erase standard.
NAVSO P-5239-26 is performed in 3 steps:
INFOSEC 5 BASELINE SECURE ERASE
INFOSEC 5 BASELINE is a secure erase standard used by the British government.
INFOSEC 5 ENHANCED SECURE ERASE
INFOSEC 5 ENHANCED is a secure erase standard used by the British government.
Rocket gives you the chance to perform secure erase on any computer connected device or logical drive.
Secure erase of clones
Secure Erase is mandatory for all cloning tasks from damaged devices, where skipped sectors cannot be readed from source and will be not transferred on targed devices.
