未检测到写入 mifare 1k 卡的 Ndef 数据

Question

I have written Ndef data in a Mifare card, I want it to be readable by any android device having NFC support, irrespective of whether if supports Mifare cards.

Some of the phones like Honor 8 pro(Does not have Mifare support) can read the tag but others like Samsung J7 are not able to read it.

I have attached card data in an image. I have made the sector 2 and onwards private by using a non-standerd key

public void onTagDiscovered(Tag tag) {
// This is getting called for all devices
 Ndef ndef = Ndef.get(tag);
}

ndef is null in Samsung j7, whereas it has an object in Honor 8 pro.

Any idea why this might be happening or any other way to achieve this?

Answer 1

Note, that on some mobile phones the OS doesn't report Mifare support, although Mifare Classic cards can be read just fine. Android is supposed to report the com.nxp.mifare system feature, if Mifare support is present, but some phones don't.

Some apps like NFC Check by Tapkey therefore sometimes report Mifare support as absent, although it's present. To be clear, this is not these apps' fault but rather the fault of the OS. Some older Moto phones are known to have this issue. According to your description it seems, that the Honor 8 pro has the same issue too, otherwise it wouldn't return an Ndef instance. On the other hand, probably the Samsung J7 actually really doesn't support Mifare, which is why it doesn't return a Ndef instance.

From your question I infer, that you are talking about Mifare Classic cards. Note, that in contrast to Mifare Classic, other Mifare cards, ie Mifare DESFire cards, can act as Type 4 NDEF tags and can therefore even be read by phones that don't have support for the proprietary Mifare classic. This is because Type 4 NDEF tags are standardized. They are based on the standardized ISO 7816 protocol and are supported by close to all NFC-enabled phones.

So making a long story short, probably you won't be able to read Mifare classic cards with phones that really don't have Mifare support while reading cards like the Mifare DESFire should work just fine. Other pros of the DESFire are, that they are more secure, bigger in size and more flexible. The biggest downside is, that they are significantly more expensive.