The tech involved is deceptively simple: evolved from radio frequency identification (RFID) tech, an NFC chip operates as one part of a wireless link. Once it's activated by another chip, small amounts of data between the two devices can be transferred when held a few centimeters from each other. No pairing code is necessary to link up and because it uses chips that run on very low amounts of power (or passively, using even less), it's much more power-efficient than other wireless communication types.