what is an application aid Mifare DESFire ev1

MIFARE DESFire EV1 can have multiple applications (28), and each application can have multiple files (32) of different types (4). The card itself has a PICC master key plus between 1 and 14 keys per application. The keys of each application are used to control access to its files.

A Mifare DESFire EV1 card can hold up to 28 different applications and 32 files perapplication. The size of each file is flexible. An access control system requires justone file within one application so the same card could also be used for other appli-cations such as vending, ticketing or banking, provided by other suppliers.Our readers support DESFire EV1 cards of size 2 kbytes, 4 kbytes or 8 kbytes. Anapplication on a DESFire EV1 card is identified by a 6 digit hexadecimal numberknown as the application identifier (AID). The AID is programmed into the card atenrolment and the reader is configured to use the same AID. Within the chosen application, the card is pro-grammed with a data file at enrolment. This file is given an identifier (file ID) whichis any hexadecimal number chosen in the range 00 to 1F. The reader must be con-figured to look for the same file ID. The data file contains a number, all or part ofwhich can be used as the ID number. The reader reports the ID number to the ac-cess system controller which uses the ID number to recognize the user.The data in the file is secured by a read encryption key of your choice. This key notonly enables the data to be read from the card but also enciphers data transmis-sion between the card and the reader. Free directory list access without master keyhas to be allowed by the DESFire EV1 card. The application that contains the filewith the ID number shall be accessed using AES mode. The communication modewith the file that contains the ID number has to be fully enciphered. The key to beused for read access has to be defined. The key to read out the ID number has tobe the same as the one to access the application. The reading key is 16 byteslong.

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