Secure Data Erasure
In an age where data security is paramount, the common perception is that physical destruction is the only surefire way to ensure the complete eradication of data from hard drives. However, this belief is increasingly being challenged by advancements in data erasure technology. Contrary to popular opinion, hard drives do not need to be shattered into pieces to render their data irretrievable. Secure data erasure methods, which comply with stringent standards such as those set by the U.S. Department of Defense, offer a reliable alternative that not only protects sensitive information but also supports sustainability by allowing hard drives to be repurposed and avoid the landfill. This section explores how these secure erasure techniques work and why they are a viable, eco-friendly option for safeguarding data.Magnetic Hard Drives
Magnetic hard drives, also known as platter hard drives or “spinning rust”, have been a cornerstone of data storage technology since their invention by IBM in 1956. These drives utilize spinning magnetic disks, or platters, to store data, with read/write heads that access the information, similar to how a vinyl record is played. The data on a magnetic hard drive is stored as a long series of 1s and 0s called bits. To give you an idea of the magnitude of these bits, it would take approximately 8,388,608 bits to store a 1MB image on a hard drive. The average hard drive can hold 17,592,186,044,416 bits of data.Over the decades, magnetic hard drives have evolved significantly, increasing in storage capacity and efficiency while becoming more compact. Despite the rise of solid-state drives (SSDs) in recent years, magnetic hard drives continue to be widely used due to their cost-effectiveness and large storage capacities, making them the logical choice for many applications in both consumer and enterprise environments.Sources
Secure erasure of magnetic hard drives can be achieved simply by overwriting the 17,592,186,044,416 bits of data on a hard drive with all 0s or all 1s. While many popular erasure techniques involve erasing the drive two, three or even seven times, studies have confirmed it's actually a matter of "quality" over "quantity" - one proper pass over the drive with 0s, 1s, or pseudo-random data is sufficient to permanently and irrecoverably remove data from a magnetic hard drive.What often occurs is that a particular piece of hard drive erasure software skips certain portions of the drive during the erasure process. Less-likely are unintentional, interrupted drive erasures such as a power outage occurring during the erasure process. In either case, the erasure is incomplete and data can still be recovered from the drive. To mitigate these risks, it is recommended that the erasure is verified before the drive is considered clean and ready to repurpose.Solid-State (Flash) Drives
Solid State Drives (SSDs) represent a significant advancement in data storage technology, offering superior performance and reliability compared to traditional magnetic hard drives. Unlike their mechanical counterparts, SSDs have no moving parts and utilize NAND flash memory to store data, resulting in faster read and write speeds, reduced power consumption, and greater durability. First introduced in the late 1980s, SSDs have become increasingly popular in recent years due to their efficiency and the decreasing cost of flash memory. They are commonly used in various applications, from personal computers and laptops to enterprise data centers, providing a robust solution for high-speed data access and storage.As with magnetic hard drives, complete, irrecoverable erasure of solid-state flash memory (including flash drives and SSDs) can be achieved using the proper processes. Because NAND flash memory has a finite number of writes it can handle, it is not recommended nor necessary to "zero-pass" (write 1s or 0s) an SSD or flash drive as we would a magnetic hard drive. In fact, in the case of SSDs, a small "computer" located on the SSD itself called the controller manages the array of NAND flash within the SSD to ensure wear-leveling (equal wear of the NAND flash chips), error management, and encryption of the data stored on the SSD. We can leverage this, paired with the physics of how data is stored on flash memory (using voltage rather than magnetism) to quickly and completely erase an SSD or flash drive without exposing it to unnecessary wear.Fun fact: Without electricity, the data on an SSD or flash drive will eventually "evaporate"- erase on its own. This usually happens after 5-10 years (varies by manufacturer) of not being connected to a power source (e.g. a computer). This is why magnetic hard drives are the superior choice for long-term storage detached from a computer or server.
“An Evaluation Of Data Erasing Tools”
“The permanent removal of data from media is a major area of concern mainly because of the misconception that once a file is deleted or storage media is formatted, it cannot be recovered. There has been the development of both commercial and freeware data erasing tools, whichall claim complete file or disk erasure. This report analyzes the efficiency of a number of these tools in performing erasures on an electromechanical drive. It focuses on a selection of popular and modern erasing tools, taking into consideration their usability, claimed erasing standards, and whether they perform complete data erasure with the use of the Write Zero method.”
“Do SSD disks actually require regular power lest they "forget" their data?”
“When unpowered, SSDs indeed do have a limited data retention period. This varies a lot depending on the SSD type and on the temperatures during operation and when unpowered...”
“The easy and fast way to securely remove all data from your SSD”
“This is not an overwrite. It is a true erase of the media. Each targeted storage element is raised to an erase voltage (significantly higher than the standard program voltage), then that signal is dropped to ground, leaving no trace of the previous signal. After this, the storage element is now in a state where it is ready to be programmed with new data from the host computer…”