How do contactless smart cards work?
Contactless smart card systems are closely related to contact smart card systems. Like contact smart card systems, information is stored on a chip embedded within the contactless smart card. However, unlike the contact smart card, the power supplied to the card as well as the data exchanged between the card and the reader are achieved without the use of contacts, using magnetic or electromagnetic fields to both power the card as well as to exchange data with the reader. The contactless smart card contains an antenna embedded within the plastic body of the card (or within a key fob, watch or other document). When the card is brought into the electromagnetic field of the reader, the chip in the card is powered on. Once the chip is powered on, a wireless communication protocol is initiated and established between the card and the reader for data transfer. The following four functions describe at a high level the sequence of events that happen when a contactless smart card is brought near
