In the United States, our credit and debit cards still rely on outdated magnetic stripe technology. The magnetic stripe is the black or brown band on the back of your credit or debit card. The stripe stores data, such as your account number, via tiny, iron-based magnetic particles. When you swipe your card through a card reader, the device accesses the data stored on the magnetic stripe. A quick YouTube search yields numerous vendors offering to sell skimming devices, which can be used to steal data from credit cards as they are swiped in an ATM.