One of the most iconic scenes in the hit TV series Breaking Bad involves the characters using an industrial-sized magnet to destroy evidence stored on laptop hard drives. In the climactic scene, a truck outfitted with a massive magnet is driven next to a police evidence locker to corrupt the data on hard drives inside.
This visually stunning scene captures the imagination of viewers and raises the question – can you really destroy or erase data on a hard drive using a strong magnet? The scene taps into the common conception that magnets can scramble and destroy electronic data, but just how feasible is this in real life?
How Hard Drives Store Data
Hard drives store data using magnetic recording heads and spinning platters coated with magnetic material (1). The platters are made from non-magnetic material like aluminum or glass and are coated with a thin layer of magnetic material like cobalt-based alloy or iron oxide (1).
The magnetic recording heads, commonly known as read/write heads, are responsible for modifying the magnetic properties of the platter’s coating in specific spots as the platters spin underneath them. These heads have tiny electromagnets that can polarize small regions on the platter to represent binary data – a 1 or 0 (2). By polarizing the magnetic coating into distinct regions of magnetic north and south poles, the drive is able to precisely control how data is written and later retrieved.
The hard drive’s platters are organized into concentric circles called tracks, which are further divided into sectors. This allows data to be written in an orderly fashion across the platter’s surface. The drive’s electronics position the heads precisely over these tracks and sectors to read or write the data. In this way, hard drives are able to store large amounts of data in a relatively small area.
Sources:
(1) https://www.explainthatstuff.com/harddrive.html
(2) https://cs.stanford.edu/people/nick/how-hard-drive-works/
Magnetism and Data Destruction
Hard drives store data on spinning magnetic platters. The data is written and read by a magnetic head that moves over the surface of the platters. The magnetic polarity of each region on the platter surface corresponds to a 0 or 1 bit value (Charterhousemuller, 2019).
Magnets can alter the magnetic charge of these regions, essentially scrambling the data. Strong magnets in close proximity to a hard drive can corrupt data across large sections of the platter, rendering files unreadable. According to US Magnetix (2022), the strength of magnet you need is actually quite dangerous. Anything with a pull force of 7 pounds or higher is enough to pinch your fingers or damage electronics.
Magnet Strength Required
A hard drive stores data by using a magnetic head to polarize tiny magnetic domains on the hard drive platter. The density of hard drives has increased over the years as technology has advanced, with modern drives having domain sizes around 10-20 nanometers and requiring about 10-20 tesla of field strength from the magnetic head to polarize the domains for writing data.
To damage or erase the data stored on a hard drive using an external magnet, you need a magnet that can generate a strong enough field within the drive’s cover to overcome the existing magnetic polarity of the domains. According to industry experts, this requires a magnet with a field strength of several thousand gauss when placed directly on the drive.
For example, K&J Magnetics indicates neodymium rare earth magnets generating 3,000-5,000 gauss of field strength are typically needed to damage or erase a hard drive. Consumer-grade neodymium magnets generate up to around 1,400 gauss maximum, while industrial neodymium magnets can reach field strengths over 10,000+ gauss. So industrial-level rare earth magnets would likely be required for magnetically destroying data on a hard drive.
Other Factors
The distance between the magnet and the hard drive is a crucial factor. The magnetic field strength drops off rapidly with distance, so a powerful magnet held an inch away may have no effect, while the same magnet touching the drive could cause corruption. Generally, the magnet needs to be within a couple millimeters to have any impact.
The size of the magnet also matters. A larger magnet concentrating its flux in one area can overwhelm a small section of the platters. But a small neodymium magnet likely won’t affect an entire multi-platter drive, even in direct contact.
Orientation and direction of magnetization affects field alignment. A magnet swiped linearly past the drive introduces rapidly changing fields that may flip bits. Whereas a magnet sitting stationary on top aligns with the drive’s own field and causes less disruption. Rotating the magnet can induce more errors.
In summary, the risk depends on the magnet strength, size, distance, orientation, and duration of exposure. But data destruction is unlikely with casual exposure. It requires strong fields applied in close proximity with deliberate orientation.
Is Complete Erasure Possible?
While magnets can corrupt and damage hard drives, completely erasing all data is challenging. According to Can a Magnet Really Erase a Hard Drive?, even strong rare earth neodymium magnets may not fully erase a modern high-capacity hard drive. Data recovery experts may still be able to recover data from platters damaged by magnets.
For the best chance of complete erasure, professional degaussing is recommended. Degaussing exposes the hard drive to an alternating magnetic field, efficiently demagnetizing the surface. The U.S. Department of Defense standards specify that degaussing must render hard drives unusable and data unrecoverable. However, degaussing requires specialized equipment not readily available to consumers.
While magnets can corrupt drives and make data recovery expensive, they do not guarantee complete erasure. For full assurance of erasure, physical destruction or professional data wiping services would be more reliable options.
Dangers to Other Electronics
Although magnets would need to be extremely powerful to damage most electronic devices, they can pose risks to data storage on items like credit cards and hotel room keys. The magnetic stripes on the backs of credit cards, debit cards, ID cards, and room keys contain data programmed by precise orientations of iron oxide particles. According to Amazing Magnets, strong neodymium magnets can “damage certain magnetic media such as credit cards, magnetic I.D. cards”. Even being in close proximity to the magnet can rearrange the magnetic particles and corrupt the data. The American Association of Printed Circuit Boards also warns that “Strong electromagnets can damage electronic components by stripping away the device’s programming”. This makes it vital to keep high-powered magnets at a safe distance from items like credit cards in your wallet or purse.
Legal Implications
There are some legal considerations when it comes to using magnets to intentionally destroy data stored on hard drives. According to the U.S. Department of Commerce’s National Institute of Standards and Technology (NIST), there are guidelines that recommend degaussing or securely overwriting hard drives before disposing of them to prevent unauthorized access to sensitive data (https://usmagnetix.com/can-a-magnet-really-erase-a-hard-drive/).
While individual consumers are not typically held to these standards, businesses and organizations that deal with sensitive data may be legally required to scrub or destroy hard drives in accordance with regulations like HIPAA, GLBA, SOX, and PCI DSS. Using magnets to attempt to erase hard drives could violate data security laws if it is found to be an insecure method of data destruction (https://charterhousemuller.com/4-facts-about-destroying-computer-hard-drives/).
The U.S. National Security Agency suggests that magnets alone should not be relied upon for proper hard drive sanitization. Instead, they recommend steps like cryptographic erase or physical destruction of hard drives. Businesses should consult with legal counsel to ensure compliance when disposing of digital assets.
Data Recovery Methods
There are several techniques that may be used to attempt recovering data from a hard drive damaged by magnets. However, success is not guaranteed.
One method is to try removing the platters from the damaged hard drive and placing them into an identical working drive to gain access. This requires very specialized tools and expertise to not further damage the platters during removal and transfer. Even if successful, some data loss or corruption has likely occurred.
Another option is to utilize professional data recovery services that have specialized clean room facilities and advanced equipment to repair drives and reconstruct data. However, costs often start around $300 and increase based on drive size and damage level. There are no guarantees data can be fully retrieved if magnetic damage is severe.1
Lastly, if the drive electronics remain intact, recovery software may be able to repair the file system and disk enough to copy any retrievable data. But this only works if the physical platters and data encoding have not been corrupted beyond repair.
In summary, while data recovery is sometimes possible, results are uncertain with magnetically damaged drives. Prevention through proper data backups is more reliable.
Conclusions
In summary, while magnets pose some level of threat to hard drives and data destruction, a typical household magnet is highly unlikely to irreparably damage most modern drives by itself. Only large industrial-grade magnets with extremely powerful magnetic fields would reliably degauss a drive and cause permanent data loss.
That said, magnets should still be kept far away from all electronics and storage media, as they can corrupt files and make data retrieval expensive and difficult. While unlikely to succeed alone, magnets can potentially enable data destruction when used in conjunction with more reliable methods.
The takeaways are:
- Standard household magnets are generally too weak to reliably destroy a modern hard drive’s data.
- Industrial-sized neodymium magnets with very powerful fields pose a real degaussing threat but are not easily obtained by most.
- Magnets should never be casually tested on live drives due to the risk of data corruption.
- If magnets are utilized for data destruction, use them only in addition to more reliable techniques like disk shredding.
- Be aware of applicable laws regarding illegal data destruction and the proper wiping of drives.
- With the right recovery methods, deleted data is often still recoverable regardless of magnetic damage.