How do RFID wallets work

Wallet with RFID protection compartment

Arne Arnold

If you have two RFID cards in your wallet, you will confuse most readers. A protective cover creates order here.

EnlargeThis credit card-sized cover protects cards from RFID readers. All of your own RFID cards can be inserted in it, or only those that you rarely need.

If you want to make contactless payments at a supermarket checkout with your RFID credit card, you often have to take the card out of your wallet so that the reader can recognize it. The reason is not due to the radiation protection effect of your own leather wallet, but to an additional RFID card in the bag. Chances are that you have two such cards in your pocket. Because cards with RFID chips (Radio Frequency Identification) are now widespread. The car sharing service Drive Now has an RFID chip built into its customer card as well as many access and digital stamp cards for the office. But if there are two RFID cards in your wallet, both are encouraged by the radio waves from the till reader to send their data back to the reader. The reader cannot do anything with this duplicate information and therefore stops the action.

However, there is a trick you can use to keep the RFID payment card in your wallet so that you can hold it completely against the reader: You only have to protect the other cards against radiation from the reader. This is quite easy with an RFID protective cover, which can be bought for a few euros. With the advent of the new RFID cards, many users feared unwanted debiting of money. This is how wallets came onto the market that are completely protected against RFID readers. But there are also cases in credit card format that fit exactly one or two cards. Put the cards you rarely need in this case and leave only the regularly used RFID card unprotected. In the wallet, the protective cover should ideally be a bit away from the card used and you have to remember which side the protective cover is on in the wallet. Because you then have to hold the wallet with the other side to the reader.

Aluminum foil is sufficient: Most protective sleeves are lined with simple aluminum foil. This is enough to weaken the radio waves from the reader to such an extent that the passive RFID chip on the card can no longer send an answer. As Stiftung Warentest has found out, even a few layers of household aluminum foil are sufficient to achieve the same protective effect. You can therefore easily tinker your own protective cover yourself.

By the way, if you have a new identity card, you don't have to worry about RFID espionage. Because in order to be able to read the data from the new ID card via RFID, you need a PIN. Only stately places do not need this PIN. In order to read the data, they first need a code that is printed on the passport and, secondly, a special certificate.