ISO/IEC 7816-3 defines the transmission protocol between chip cards and readers. Using this protocol, data is exchanged in application protocol data units (APDUs). This comprises sending a command to a card, the card processing it, and sending a response. EMV uses the following commands:
- application block
- application unblock
- card block
- external authenticate (7816-4)
- generate application cryptogram
- get data (7816-4)
- get processing options
- internal authenticate (7816-4)
- PIN change / unblock
- read record (7816-4)
- select (7816-4)
- verify (7816-4).
Commands followed by "7816-4" are defined in ISO/IEC 7816-4 and are interindustry commands used for many chip card applications such as GSM SIM cards.