Ultralight C-lock Mifare

Question

I am trying to block the Mifare Ultralight C label. I want to set the NDEF pages 0x04 to 0x27 for read only. I think this can be achieved with help Ndef.makeReadonly().

In addition, I would like to set the pages 0x29 to 0x2F for password protection (for reading and writing), so that they can only be obtained after successful authentication. I am trying to understand what bytes need to be set in lock bytes (page 0x28, bytes 0, 1), and if it is necessary to set sectors 0x2A and 0x2B as well.

Answer 1

I am trying to set NDEF pages 0x04 to 0x27 for reading. I think this can be achieved with Ndef.makeReadonly ().

Optional, Ndef.makeReadonly()can only set the read-only flag in the capabilities container (according to the NFC Forum Type 2 Tag Operation specification).

If you want to set the actual lock bits, you must connect the tag as a tag technology NfcAor MifareUltralightinstead execute the write command for the lock bits.

NfcA nfcA = NfcA.get(tag);
nfcA.connect();

byte[] result1 = nfcA.transceive(new byte[] {
    (byte)0xA2,  /* CMD = WRITE */
    (byte)0x02,  /* PAGE = 2    */
    (byte)0x00, (byte)0x00, (byte)0xFF, (byte)0xFF  /* DATA = lock pages 3..15 */
});

byte[] result2 = nfcA.transceive(new byte[] {
    (byte)0xA2,  /* CMD = WRITE */
    (byte)0x28,  /* PAGE = 40   */
    (byte)0x0F, (byte)0x00, (byte)0x00, (byte)0x00  /* DATA = lock pages 16..27 */
});

Also see Mifare Ultralight: Lock specific pages to encode the lock.

I would like to set the 0x29 pages to 0x2F for password protection (for reading and writing) so that they can only be retrieved after successful authentication.

, , 44..47. AUTH1 (. 43) . , AUTH0 (. 42) 0x29 0x00 0x00 0x00, 41 . 40 , . (.. 0x1F 0x0F 0x00 0x00 . 40), .