How to Avoid a Demagnetized Key Card or Key Fob

By Bernhard Mehl
June 10, 2018

A couple of people told me recently that their company ID cards (RFID-based) had stopped working. When I asked them if they had called their security company, they said they did and the recommendation was to keep their company badge separate from other cards in their wallet. However most people obviously put their access card into their wallet for convenience. The problem with this is that, in a wallet, when an access card inevitably comes into contact with credit cards, this may cause demagnetization or desensitization. We call this a demagnetized card.

The Card in Wallet Problem: RFID Interference

When looking on Quora, people report similar things: “I have three different ID badges, all with RFID in them. They are all currently in my wallet. When I try to use them, they interfere with each other and the scanner does not read my card. This happens even when I take all three out, put them together and try to scan a card. When I scan the correct card alone, it works flawlessly.  Is there a way I can address this?”

Some people have these issues especially with hotel key cards which are based on 125khz frequencies (and especially easy to hack by the way). There are speculations whether a smartphone can actually cause a demagnetized card. Based on the stories. it seems like this is happening more often with low frequency cards. As a workaround (besides buying more expensive cards or readers), people suggest to use aluminum foil and cover the card with that.

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Other Modes for Demagnetization

Decorative Magnets

RFID interference is a common, but not the only way your access card can get demagnetized. If you recall some basic middle school physics, every magnet has a magnetic field created by electrons moving between the two poles. When one magnet comes close to another, it affects the other card’s magnetic field. With a mag stripe card, this same principle applies when it comes into contact with other magnetized objects (like credit and debit cards, key chains, etc...) and thus results in the card being demagnetized and the data erased. A swipe card can get demagnetized even from something as simple as a fridge door magnet, provided you keep them close enough for a long time.

Clothes and Accessories Magnets

Magnets on wallets, jackets and purses are convenient as they do a great job closing a compartment and keeping it tightly sealed. A great place to keep your access cards safe, right? Not always. If the card is affected by the magnetic field of a magnetic zipper or button it can get demagnetized. This scenario happens because people usually keep their stuff together in a bag or carry them in their pockets. For the card to malfunction, it needs to be in really close contact to such magnets, so, for the most part, they are safe in your bags.

Security Tags

New clothing is a common but little-known culprit for ruining magstripe cards. It can create additional problems when you bring an access card close to the security tag deactivator in a retail store’s checkout location. For example, say you are handing over your credit card to the cashier while holding your wallet in the same hand. As it passes over the deactivator, the credit card and every magnetized card in your wallet is at risk of having their magnetic fields disrupted by the strong magnet near the cashier's station. This is a rare occurrence since stores don’t always use a deactivating technology that can mess with a magnetic field. But just to be sure, pick up your wallet from the cashier’s desk immediately after completing a purchase.

MRI Scans

Needless to say, an MRI machine is much stronger than the previous magnets mentioned. MRI equipment can demagnetize cards even if they are brought as close as 5 or 6 feet, which means that an MRI room can pose a risk to all the magnetized cards on you at the moment and erase your data.

Physical Damage

Physically damaging a card is perhaps the most common cause for dysfunction. The magnetic stripe has an iron film, which, when scratched, makes the data unreadable and the magnetic card reader won’t be able to process the data at all. This is another reason it's not recommended to keep your cards exposed in the same pocket as your keys or other metal objects in a bag.

Possible Solutions to Avoid a Demagnetized Card

Before jumping ahead with more expensive solutions, you can also go to your security department and ask if they activated the anti-RFID Tag collision algorithm on their readers. Basically this enables technology to keep radio waves from one device from interfering with radio waves from another device. Not going too deep into this, but for example an adaptive hierarchical artificial immune system and build the basis for such an algorithm. There are even RFID-blocking wallets. One of the more drastic solutions we’ve found is to extract the RFID coil and chip from the card and just mount it into your smartphone – that way you can store your RFID transit card in your smartphone. Some people would call this RFID transplantation. Without tampering too much with access card itself, the best way to keep it protected is to wear it like a employee badge in a plastic enclosure clipped to your chest. Your security guys will love it!

A very simple way to protect a magstripe card is to put it in a paper or a plastic sleeve. You can also use a wallet-type credit card holder and keep the cards facing the same direction in order to avoid potential inflictions or scratches.

Use wallet to protect magstripe card
‍Use a wallet credit card holder to protect your card

Mobile Access Control as a Solution

Although cloud access control systems are usually installed to solve far more complex issues than this, Kisi's mobile access solution allows users to access any door with a tap of their smartphone, which, unlike key cards, does not demagnetize! In addition, admins can regulate access rights easily and the risks of lost cards or key fobs are taken out of the picture. You can find more information about our product here!

Additional Benefits of Cloud Access

Cloud-based access has benefits both on the admin side and on the user side.

If you manage an access control system that grants access with a smartphone, you won’t ever need to worry about demagnetized, lost, stolen or otherwise dysfunctional access cards unless you prefer working with cards. This cloud-based system works with cards, too. Each user’s smartphone gets a code from a central dashboard which you, as an admin can control from one location. You can control unlimited doors or up to four doors and windows with a single controller. The best feature is that you can grant, share and revoke access in real-time, following everything from the app on your desk or on your mobile.

Of course, this doesn’t need to happen in one office - cloud access can be distributed to multiple sites. Finally, you can schedule and audit the changes you’ve made, assign multiple admin roles and get alerts about faulty access attempts.

User-facing benefits from cloud access include versatile access options. You can use anything you like - cards, fobs, a smartphone, even links, as a single option or all at once to enter your secured spaces. The access system supports Bluetooth technology for iPhone and NFC for Android smartphones.  With this fully mobile functionality, no physical key cards or fobs are necessary.

Fix or reorder demagnetized cards?

Demagnetized cards are not extremely expensive. However, as a general rule, it’s not recommended to fix them. Some people recommend applying a simple life hack, such as putting some tape over the magnetic stripe, but this is no guarantee that the card will work. As you know, access cards contain a minimal amount of identification info, so the company that printed it usually keeps the data and will be able to replace it for an affordable sum. However, it will take some time to complete all this. Until then, you won’t be able to get access and do your job as usual. Smartphone access control systems solve this problem because they are much sturdier and are able to provide access with a code that can be granted or revoked at any time, minimizing the risk to both the company and the user. Cards that get damaged must be destroyed when not in use - so, get those scissors!

Relevant Links

Bernhard Mehl

Bernhard is the co-founder and CEO of Kisi. His philosophy, "security is awesome," is contagious among tech-enabled companies.

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