DESFire®
The MIFARE transponder operates at a range of up to 10 cm and uses a frequency of 13.561 MHz.
A MIFARE product-based card does not require a battery and is powered by the oscillating electromagnetic field of the base station (read/write device). A wire coil integrated into the transponder absorbs the necessary energy as it passes through the electromagnetic field. For communication, the transponder modulates and demodulates the excitation field of the base station (read/write device).
The memory of the MIFARE Classic product-based card is divided into several sectors, each independently protected against unauthorized reading and writing. The sectors are further subdivided into several blocks of 16 bytes each. The last block in each sector is called the sector trailer and contains two keys (authorization levels) and the corresponding access conditions for that sector. This mechanism allows one MIFARE transponder to operate several different applications ("multi-application").