Reading NTAG213/MifareClassic

[mbigant]

Hi,
I'm trying to read NTAG213 and MifareClassic card but issuing an java.lang.NullPointerException in AndroidNfcReaderAdapter.kt:94.
After some researches I found that tagTechnology is null and I notice that it is not set (like currentCardProtocol also) in every case in the onTagDiscovered method.

override fun onTagDiscovered(tag: Tag) {
    logger.info("{}: card discovered: {}", name, tag)
    isCardChannelOpen = false
    try {
      for (technology in tag.techList) when (technology) {
        IsoDep::class.qualifiedName -> {
          currentCardProtocol = IsoDep::class.qualifiedName!!
          tagTechnology = IsoDep.get(tag)
        }
        MifareUltralight::class.qualifiedName -> {
          currentCardProtocol = MifareUltralight::class.qualifiedName!!
          tagTechnology = MifareUltralight.get(tag)
        }
        NfcA::class.qualifiedName -> {
          val tagA = NfcA.get(tag)
          uid = tagA.tag.id
          powerOnData =
              JSONObject()
                  .put("type", "A")
                  .put("uid", HexUtil.toHex(uid))
                  .put("atqa", HexUtil.toHex(tagA.atqa))
                  .put("sak", HexUtil.toHex(tagA.sak))
                  .toString()
        }
        NfcB::class.qualifiedName -> {
          val tagB = NfcB.get(tag)
          uid = tagB.tag.id
          powerOnData =
              JSONObject()
                  .put("type", "B")
                  .put("uid", HexUtil.toHex(uid))
                  .put("applicationData", HexUtil.toHex(tagB.applicationData))
                  .put("protocolInfo", HexUtil.toHex(tagB.protocolInfo))
                  .toString()
        }
        else -> logger.warn("{}: unreachable code", name)
      }
      cardInsertionWaiterAsynchronousApi.onCardInserted()
    } catch (_: NoSuchElementException) {
      tagTechnology = null
      logger.warn("{}: unsupported card technology", name)
    }
  }

When matching NfcA or NfcB which is my case there is no tagTechnology affectation. Is there any reason ?

Thank you.

[jeanpierrefortune]

Hi,

Thank you for this detailed analysis.

Could you please check if this issue still persists with the latest version 3.2.0 of the library?

Additionally, could you clarify your needs: is full support for NTAG213 and MifareClassic cards a requirement for your application, or do you simply need the application to ignore them without crashing?

Note that support for "Storage Cards" has recently been introduced via this API: https://github.com/eclipse-keyple/keyple-plugin-storagecard-java-api/. However, you will need to provide an APDU interpreter to access proprietary commands through APDUs.

Best regards

[pterr]

The Calypso Networks Association, a non-profit organization, is the main sponsor for the development of the Eclipse ‘Keypop’ and ‘Keyple’ projects.

With Keypop, we have defined high-level APIs for ticketing terminals. In particular, the ‘Reader API’ and ‘Card API’ can be extended to design specific extension libraries to support secure processing for any smart card solution.
The core ‘Service’ component of Keyple is able to integrate any kind of smart card solution extension in a generic way, independently of reader solutions, thanks to the Plugin API.

For the integration of smart card solutions based on standard communication protocols such as ISO 14443-4 or ISO 7816-3 and with a set of commands based on the APDU format of ISO 7816-4, adding the card extension is easy without any particular constraints on plugins & reader solutions.

As you point out, there are NFC tags or contactless memory cards based on proprietary communication protocols. Some members of the CNA association, who need to manage ISO card solutions with non-ISO memory cards (ST25, CT512, Mifare UltraLight, Mifare Classic), have asked us to support these proprietary solutions with Keyple.
The PC/SC standard has a “Storage Card” product class with a method for encapsulating commands based on byte blocks in APDU envelops. We took inspiration from this method to offer a command wrapping solution for memory cards that can work uniformly for all reader solutions, PC/SC or others.
We have released the Keypop “Storage Card API” which allows reading or writing to various contactless memory card solutions: ST25, CT512, Mifare Ultra-Light, and Mifare Classic. This API provides simple access to generic features for all these product varieties: simple reading or writing of byte blocks.
The NTAG213 (144-byte memory) appears to be a solution derived from the MIFARE Ultralight EV1 (48 or 128-byte memory). Basic reading or writing to an NTAG213 should be possible by identifying the card as a Mifare Ultra-Light through the Storage Card API.
If you need to perform other advanced functions specific to the NTAG213 product, I would advise you to design your own card extension in Keyple by following the dedicated guide. You will then define an advanced API specific to NTAG213 (you can reference your interfaces on the Keypop project if you wish), and you will develop a card extension library integrating advanced NTAG213 features (whether your implementation is open source or closed, you also have the option of referencing your extension libraries on the Keyple project).

To facilitate the design of plugins for reader solutions supporting proprietary contactless memory card communication protocols, we have published the “Plugin Storage Card API” interface in Keyple. This interface integrates support for a library into various plugins to manage the APDU encapsulation of byte block-based commands for memory card solutions.

Android NFC readers do not support ST25 or CT512 type cards. However, Android NFC readers do support Mifare UltraLight and Mifare Classic memory cards, among others. We have adopted Keyple's Android NFC plugin to manage these two types of memory cards.
If you need to operate NTAG213 memory types:

• Either you only need basic write or read access, in which case you can use the current plugin, identifying your NTAG213 cards as Mifare UltraLight.
• Otherwise, if you need more advanced access, you may need to update this Keyple plugin to support NTAG213. You could then make this adaptation yourself, but you will need to share your adaptations with the Keyple community as this library is licensed under EPLv2.

Regarding support for basic memory card functions, there is not yet an open-source library offering these processes. CNA has been mandated by its members to assist them with the coexistence of Calypso processes and proprietary memory cards: as referenced in Keyple's external resources, CNA offers Storage Card libraries for the exclusive use of its members.