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) started to not work anymore. When I asked them if they had called their security company, they said they did and the recommendation was to not keep the company badge in the wallet. However most people obviously put their access card into the wallet. The problem with that is that it can get in touch with credit cards and this may cause demagnetization or desensitization. We call this a demagnitized card.

The card in wallet problem

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 I way I can address this?”

Some people have these issues especially with hotel keycards which are based on 125khz (and especially easy to hack by the way). There are speculations around if the smartphone can actually cause a demagnetized card.It seems like this is happening specifically 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.


Decorative magnets

RFID interference is a common, but not the only way your access card can get demagnetized. If you remember well from a middle school physics lesson, each magnet has a magnetic field created by electrons moving between the two poles. When one magnet comes close to another, it can affect the other card’s magnetic field. This can happen with a magstripe card, ending up in having the card 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. Talking about an unforgettable Rome trip! If you are late for work only because the access card failed due to keeping it near the Rome fridge magnet, I assume you won’t be visiting Italy shortly!

Clothes and accessories magnets

Magnets on wallets, jackets and purses are convenient as they do a quick job of closing a compartment and keeping it tightly sealed. A great place to keep your access cards safe, right? Not always. If the card gets affected by the magnetic field of a magnetic zipper 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 get dysfunctional, it needs to get really close to such magnets, so, you are generally safe.

Security tags

Clothing is quite a culprit for ruining magstripe cards. It can create additional problems when you bring a card close to the security card deactivator in a retail store’s checkout location. This is a rare occurrence since stores don’t always use a deactivating technology that can mess up with the magnetic field. Just to be sure, though, pick up your wallet from the cashier’s desk immediately after completing a purchase.

MRI scans

Needless to say, an MRI machine is not as naive as the previous magnets. Additionally, it’s not that people often take an MRI scan with the full stack of cards they use at home and at work. But - and this is a big but - 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 and get your data off of the card.

Physical damage

Physically damaging a card is perhaps the most common reason to make it dysfunctional. The magnetic stripe has an iron film, which, when scratched, it makes the data unreadable and the magnetic card reader won’t be able to process your data at all.  

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 allows different ways 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.If you want to go more professional to prevent a demagnetized card, there are even RFID blocking wallets. One of the more crazy 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 call this RFID transplantation. Probably most likely the best idea to keep it old school and if you have to wear a badge, wear it like a government employee in a plastic enclosure tagged to your chest. Your security guys will love it! However we doubt this is the future.

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 type 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 card 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 from cloud access

Cloud based access has benefits 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 have to ever need to worry about demagnetized, lost, stolen or otherwise dysfunctional access cards unless you want to because the 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 moment about this procedure 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. The access system supports Bluetooth for iPhone and NFC for Android smartphones.  You don’t need to ever think of picking up a card because you can use your mobile - a device everyone carries almost all the time.  

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, a card is some sort of identity proof, 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 provide access with a code. Cards that get damaged must be destroyed when not in use - so, get those scissors!

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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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