topic How to block create application in unauthorize state (EV3 DESFire) in NFC

How to block create application in unauthorize state (EV3 DESFire)

tanpouch — Tue, 03 Dec 2024 06:42:18 GMT

I first change the PICC master key on the first tap. Then I disconnect the card.

On the second tap to the nfc reader, I'm able to create an application without authenticating with the new PICC master key.

I want to block the application creation in an unauthorized state.
How can I do that?

Re: How to block create application in unauthorize state (EV3 DESFire)

KaiLi — Tue, 03 Dec 2024 08:18:16 GMT

Hello @tanpouch

The creation of applications is only limited by the number, and there is no way to limit permissions.

Re: How to block create application in unauthorize state (EV3 DESFire)

tanpouch — Tue, 03 Dec 2024 08:23:15 GMT

Thanks, does it mean that anyone can use the tag to create an application and then change its master key and Read/Write key to operate on it without knowing the PICC master key?

Re: How to block create application in unauthorize state (EV3 DESFire)

tanpouch — Tue, 03 Dec 2024 11:24:37 GMT

Oh, I see an option of chaging key settings, the default settings doesn't require authentication with PICC master key

Re: How to block create application in unauthorize state (EV3 DESFire)

KaiLi — Fri, 13 Dec 2024 07:33:31 GMT

Hello @tanpouch

I think you can use the ChangeKey command to change the value of the key to your own, so that even if someone creates an application, it will not be able to access it.