Yubico Forum

Hi

I'm trying to simulate my own NFC Forum Type 4 tag on a Yubikey Neo.

I played a bit with the personalization tool to set a dedicated NDEF URL - at some point the Mifare zone ended up being reset (keys A/B set to FF...FF), then with a Java Card applet using the javacardx.external.Memory standard interface to validate that I can write something into the Mifare zone.

There is apparently an NDEF Tag application already present, however it doesn't answer as expected (on all interfaces, in Mifare classic or Mifare DESfire configurations using the Windows 8 tool seen at some other place on this forum)



Now on to the questions :

- Can I fix this ?

- Can I disable the d276000085010100 application and code my own ? (preferred, as I would like mine to avoid answering on the contact interface)

Thanks for your help

The NDEF type 4 tags are handled through APDUs on the ISO14443-4 layer and in order to support these, we've added an NDEF applet with AID D2760000850101. The operation is described in the NFC forum document "Type 4 Tag Operation Specification", which can be downloaded at their website.

This applet can be removed or replaced with your own applet of choice of you want. Just be aware that you cannot restore our NDEF applet, thereby losing the possibility to get NDEFs with embedded OTPs.

The current NEO does not feature Mifare DesFire support, but you can use Mifare Classic if you want. Then, in order to not confuse your reader (unless you have full control of that), you probably need to change the ATQA and SAK responses to let the host believe you have an ISO14443-3 only tag. Then, you can use the Mifare Classic ISO14443-3 NDEF tag type 2, if that is what you want.

Do you have a Windows 8 phone ? That one gets a bit confused by the "hybrid" Mifare Classic emulation. If you send the following APDU to the NEO, it will change the SAK and ATQA responses to please the W8 phone - 80e2800007df3504a5034420

Please let me know if this answered your questions in a satisfactory way.

Best regards,

JakobE
Hardware- and firmware guy @ Yubico

Hi

Thanks for the detailed answer

I just realized that I didn't delete the correct AID when trying to delete it, so it's fixed.