Locked desfire card and ndef messages Android

Question

I am trying to create an Android application that handles the desfire cards. I have implemented some methods that let my authenticate, create applications etc. Until now all the communication with the card is done using the IsoDep object and the tranceive() command. I know that the desfire is an Nfc Forum Type 4 tag so it's supports the Ndef message structure, I have also read AN11004.

As far as I know I could communicate with the desfire, if it was not protected with a password, with the Ndef Object of Android API. How will I communicate with the locked desfire card? I know that first the authentication, select application etc. procedures will be done with IsoDep object, after that how will I manipulate with the ndef messages?

Thanks for your time!

Answer 1

How will I communicate with the locked desfire card?

Unless you know the 'unlocking'-key of the card, you can not do much with it. You will always be able to detect it, you will always be able to try to authenticate with it (will fail, because the DESfire is locked).

That's it.

For ordinary DESFire: Alll keys can be cracked within a day with a side-channel attack (needs specialized hardware). For DESFire EV-1 Tags no crack is known so far.