Read NFC Mifare Ultralight cards with javax.smartcardio

Question

I try to read NFC Mifare Ultralight cards (page 4) with an ACR1252U and the javax.smartcardio Java library this way:

TerminalFactory factory = TerminalFactory.getDefault();
List<CardTerminal> terminals = factory.terminals().list();
System.out.println("Terminals: " + terminals);

CardTerminal terminal = terminals.get(0);

System.out.println("Waiting for a card..");

if (terminal == null)
    return;
terminal.waitForCardPresent(0);

Card card = terminal.connect("T=1");
System.out.println("Card: " + card);
System.out.println("ATR: " + bytesToHex(card.getATR().getBytes()));
System.out.println("Protocol: " + card.getProtocol());

CardChannel channel = card.getBasicChannel();

CommandAPDU command = new CommandAPDU(new byte[]{(byte) 0xFF, 
    (byte) 0xB0, (byte) 0x00, (byte) 0x04, (byte) 0x04});
ResponseAPDU response = channel.transmit(command);

if (response.getSW1() == 0x90) {
    // success command
    byte[] data = response.getData();
    System.out.println(new String(data));
}

Sometimes it works and sometimes not (with the same card)

When the reading works, I get these values:

ATR = 0x3B8F8001804F0CA0000003060300030000000068
SW1 = 0x90
SW2 = 0x00

And when it doesn't work, I get these:

ATR = 0x3B80800101
SW1 = 0x63
SW2 = 0x00

Any idea what I'm doing wrong?

Michael Roland Michael Roland · Accepted Answer · 2017-03-14T07:12:05

The ATR 3B80800101 in the second case (where it did not work) indicates that the reader did not detect (or did not properly detect) the card. The ACR1252U seems to emulates this ATR only to allow connecting through the PC/SC API (e.g. javax.smartcardio) even if there is no actualy card present. This would not be possible if the reader explicitly indicated card-no-present.

The more reliably way to check if the reader detected your card (and identified it as MIFARE Ultralight) would be to parse the ATR according to the PC/SC specification (see the section on ATR for contactless storage cards):

3B 8F 80 01 80 4F 0C A000000306 03 0003 00000000 68
                     |          |  |    |
                     |          |  |    \--> RR = reserved for future use
                     |          |  \-------> NN = MIFARE Ultralight
                     |          \----------> SS = ISO 14443 Type A part 3
                     \---------------------> PC/SC RID

Read NFC Mifare Ultralight cards with javax.smartcardio

1 Answers