CODEWITHSUNDEEP
androidsecuritynfcresetjavacard
Sajith Vijesekara
Sajith Vijesekara

Reputation: 1362

How to send ATR command to reset nfc secure element using android?

i am building android application which connect to nfc secure element and get data to the android device.for building secure element i used java card API.In the jcop tools send ATR command to reset the java card.This is the sending commands.

/card -a a000000003000000 -c com.ibm.jc.CardManager
resetCard with timeout: 0 (ms)
--Waiting for card...
ATR=3B F8 18 00 FF 81 31 FE 45 4A 43 4F 50 76 32 34    ;.....1.EJCOPv24
    31 43                                              1C
ATR: T=1, FI=1/DI=8 (31clk/etu), N=-1, IFSC=254, BWI=4/CWI=5, Hist="JCOPv241"
 => 00 A4 04 00 08 A0 00 00 00 03 00 00 00 00

i am using jcop tools for that.Secure element part is complete.but my android application need to send more request to secure element at one second.I used create a tag and send data this way.

byte[] GET_STRING = { 
        (byte) 0x80, // CLA Class        
        0x04, // INS Instruction
        0x00, // P1  Parameter 1
        0x00, // P2  Parameter 2
        0x10  // LE  maximal number of bytes expected in result
    };

result = tag.transceive(GET_STRING);
int len = result.length;
if (!(result[len-2]==(byte)0x90&&result[len-1]==(byte) 0x00))
   throw new RuntimeException("could not retrieve msisdn");

byte[] data = new byte[len-2];
System.arraycopy(result, 0, data, 0, len-2);
String str = new String(data).trim();

tag.close()

But I need to know how to send ATR command using android isoDep connection. if it is not possible how to reset the java card after getting data.

Thanks Sajith

Upvotes: 0

Views: 2151

Answers (1)

Michael Roland
Michael Roland

Reputation: 40821

Regarding your terminology:

On the contactless interface, you card does not have a reset sequence that produces an ATR. However, there is two comparable events on the contactless interface. One is turning the HF field off ann on. This causes a power-loss and consequently a hard reset of the card. The second one is to put the contactless card in HALT state and re-activate the card through the activation & selection procedure as specified in ISO/IEC 14443-3. This would typically also cause a card to reset its internal state.

Regarding your question of how to reset a contactless card that is connected through Android's IsoDep:

  • Hard reset: That's only possible through bringing the card out of the NFC device's read range and then scanning it again.

  • "Soft reset": On most devices this should be possible through closing and re-opening the connection using the IsoDep instance:

    IsoDep isoDepTag = IsoDep.get(tag);

[...]

isoDepTag.close();
isoDepTag.connect();

[...]

    However, you should be avare that some device (e.g. the Galaxy S4 in combination with certain Android versions) will not properly perform a soft reset (HALT + reactivation/selection) and, instead, just continue the previous connection.

Upvotes: 1

Related Questions