Also, it might trigger fraud warnings: > Magnetic stripe cloning can be detected by the implementation of magnetic card reader heads and firmware that can read

Also, it might trigger fraud warnings: > Magnetic stripe cloning can be detected by the implementation of magnetic card reader heads and firmware that can read a signature of magnetic noise permanently embedded in all magnetic stripes during the card production process. This signature can be used in conjunction with common two factor authentication schemes utilized in ATM, debit/retail point-of-sale and prepaid card applications. -- http://en.wikipedia.org/wiki/Magnetic_stripe_card http://en.wikipedia.org/wiki/Magnetic_stripe_card It might work like a bunch of tiny electromagnets appropriately arranged on the back of the card, like pixels on your screen. These electromagnets can probably be polarized in a particular way to match the original card.