This page allows for defining which applications should be created or already exist on the DESFire card.
DESFire Applications can be added and removed with the Add and Remove buttons indicated with the red rectangle. They are characterized by their Application ID, which is a six-digit (three-byte) hexadecimal string. For DESFire EV1 cards, it is possible to specify an ISO file ID (two hexadecimal digits) and a DF name (maximum sixteen characters text). The latter two properties are not used by CardExchange when reading applications, but they can be encoded to be compliant with ISO standards. Finally, you need to specify the Number of keys to be defined for this application and the Cryptographic method (DES-triple DES, three-key triple DES or AES).
With regard to the DF Name, there is a hidden option in case you want to use a DF name that does not consist of readable ASCII text. In that case, it is possible to specify the DF name with a hexadecimal string. To indicate that you are using this option, you should start the DF name with &H or 0x, followed by the hexadecimal string.
The Processing options allow for specifying whether an application should be created if it does not exist on the DESFire chip yet, Create if not found, which is normally checked for DESFire definitions with write items that operate on blank cards. When an application is created, all its keys are set to zero and it will be necessary to check Change keys in order to set the keys to the desired values. Normally, applications can be created with the desired final key settings, but sometimes, these key settings are too restrictive. In practice, you only need to use the option Change key settings if the application master key needs to be set to a non-zero value and you do not want to allow future changes of the application master key. In that case, you create the application allowing future changes of the master key, then change the master key, and then change the key settings to not allowing future changes of the master key.
The initial and final keys and key settings can be set by clicking the respective button with three dots. The Current or initially created key settings should contain zero keys for new applications and the actual keys for existing applications, as far as these are known and needed. When creating a new application, the initial key settings should be selected such, that the configured actions in the DESFire wizard can be executed. That means that you should not restrict future changes of the master key if you still need to change the master key. For existing applications, CardExchange Press will try to read the current key settings from the card and only use the selected ones if that fails or is not allowed.
The Final key settings window is exactly the same, with the only difference that now you specify the desired keys and key settings after writing the application and changing the keys.
Note: it is not common to create applications, change keys or change key settings, if a DESFire definition only contains read items.
Note: key values can be diversified, randomized or be read from a MIFARE® SAM AV2. This is configured in the same way as already described for the PICC master key, as can be seen the section Specifying key values above.
Click Next to proceed with the creation of the DESFire Definition and go to Step 5.
