External authentication in DESFire card with ISO 7816-4 APDUs

Question

I tried to do the authentication process on a DESFire card (resident card) using ISO 7816-4 APDUs. But it always fails. Do I miss anyithing?

>>> 00 84 00 00 00 (challenge request - 5 bytes)

<<< 15 29 84 E3 6A AA A6 B7 90 00 (response of challenge 10 bytes - OK)

>>> 00 82 00 00 10 B5 02 0B 80 4F 95 CB E7 8C A6 4D E9 C1 B1 23 A7 00 (external auth request - 22 bytes)

<<< 67 00 (response of external auth - Checking error: Wrong length)

Code:

// STEP Authentication
// send initial authentication request
byte[] reqRnbEnc = new byte[]{
        (byte) 0x00,
        (byte) 0x84,
        (byte) 0x00, (byte) 0x00,
        (byte) 0x00};

// get encrypted RndB
byte[] resRnbEnc = _isoDep.transceive(reqRnbEnc);
_responseTextView.append(String.format("reqRnbEnc: %s length:%d\n", BytesToHexStr(reqRnbEnc), reqRnbEnc.length));
_responseTextView.append(String.format("resRnbEnc: %s length:%d\n", BytesToHexStr(resRnbEnc), resRnbEnc.length));

// remove 2 last characters
byte[] resRnbEncT = new byte[8];
System.arraycopy(resRnbEnc, 0, resRnbEncT, 0, 8);
_responseTextView.append(String.format("-resRnbEncT: %s length:%d\n", BytesToHexStr(resRnbEncT), resRnbEncT.length));

// decrypt RndB
byte[] resRnbDec = MyDES.decrypt(resRnbEncT);
_responseTextView.append(String.format("-resRnbDec: %s length:%d\n", BytesToHexStr(resRnbDec), resRnbDec.length));

// generate RndA
byte[] Rna = new byte[8];
new SecureRandom().nextBytes(Rna);
_responseTextView.append(String.format("-Rna: %s length:%d\n", BytesToHexStr(Rna), Rna.length));

// plain = concate RndA with resRnbDec
byte[] plain = new byte[16];
System.arraycopy(Rna, 0, plain, 0, 8);
System.arraycopy(resRnbDec, 0, plain, 8, 8);
_responseTextView.append(String.format("-plain: %s length:%d\n", BytesToHexStr(plain), plain.length));

//  cipher = encrypt plain
byte[] cipher = MyDES.encrypt(plain);
_responseTextView.append(String.format("-cipher: %s length:%d\n", BytesToHexStr(cipher), cipher.length));

// send cipher request
byte[] reqCipher = new byte[22];
reqCipher[0] = (byte) 0x00;
reqCipher[1] = (byte) 0x82;
reqCipher[2] = (byte) 0x00;
reqCipher[3] = (byte) 0x00;
reqCipher[4] = (byte) cipher.length;
System.arraycopy(cipher, 0, reqCipher, 5, cipher.length);
reqCipher[21] = (byte) 0x00;

// get response
byte[] resCipher = _isoDep.transceive(reqCipher);
_responseTextView.append(String.format("reqCipher: %s length:%d\n", BytesToHexStr(reqCipher), reqCipher.length));
_responseTextView.append(String.format("resCipher: %s length:%d\n", BytesToHexStr(resCipher), resCipher.length));

Crypto:

public class MyDES {
private static String ENCRYPTION_KEY_TYPE = "DESede";
private static String ENCRYPTION_ALGORITHM = "DESede/CBC/NoPadding";

private static byte[] key = new byte[]{
        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00,
        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00};

private static byte[] iv = new byte[]{
        (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00};

public static byte[] encrypt(byte[] plainText) {
    try {
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        SecretKey secretKey = new SecretKeySpec(key, ENCRYPTION_KEY_TYPE);
        Cipher cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
        byte[] encrypted = cipher.doFinal(plainText);
        return encrypted;
    } catch (InvalidKeyException e) {
        e.printStackTrace();
    } catch (InvalidAlgorithmParameterException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (NoSuchPaddingException e) {
        e.printStackTrace();
    } catch (BadPaddingException e) {
        e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
        e.printStackTrace();
    }
    return null;
}

public static byte[] decrypt(byte[] cipherText) {
    try {
        IvParameterSpec ivSpec = new IvParameterSpec(iv);
        SecretKey secretKey = new SecretKeySpec(key, ENCRYPTION_KEY_TYPE);
        Cipher cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivSpec);
        byte[] decrypted = cipher.doFinal(cipherText);
        return decrypted;
    } catch (InvalidKeyException e) {
        e.printStackTrace();
    } catch (InvalidAlgorithmParameterException e) {
        e.printStackTrace();
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (NoSuchPaddingException e) {
        e.printStackTrace();
    } catch (BadPaddingException e) {
        e.printStackTrace();
    } catch (IllegalBlockSizeException e) {
        e.printStackTrace();
    }
    return null;
}

score 0 · Accepted Answer · answered Dec 23 '15 at 10:22

0

The external authenticate command must not contain an Le field. As you included an Le field (last byte encoded as 0x00), you receive a wrong length error. So your command should look like:

00 82 00 00 10 B5 02 0B 80 4F 95 CB E7 8C A6 4D E9 C1 B1 23 A7

And in code:

byte[] reqCipher = new byte[5 + cipher.length];
reqCipher[0] = (byte) 0x00;
reqCipher[1] = (byte) 0x82;
reqCipher[2] = (byte) 0x00;
reqCipher[3] = (byte) 0x00;
reqCipher[4] = (byte) (cipher.length & 0x0ff);
System.arraycopy(cipher, 0, reqCipher, 5, cipher.length);

Aslo make sure that you selected the master file (master application) before starting to authenticate with the PICC master key (P2=0). Particularly as Android may have previosuly selected another application.

answered Dec 23 '15 at 10:22

Michael Roland

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Thank you sir. How to select PICC master key (p2=0)? I don't understand, I'm new bie in nfc environment. – sams Dec 23 '15 at 11:25
P2 is what you write into `reqCipher[3]`. You currently use 0x00 and therefore use the PICC master key. – Michael Roland Dec 23 '15 at 11:53
I'm selected master application before authentication process with 00 A4 04 00 07 D2 76 00 00 85 01 00. I get error 6B00 – sams Dec 23 '15 at 22:59
I'm selected master file before authentication process with 00 A4 00 00 02 3F 00. I get error 6982 – sams Dec 23 '15 at 23:00
Once again, if your card is the same as here (http://stackoverflow.com/q/34382363/2425802), your card is **not** DESFire. – Michael Roland Dec 24 '15 at 10:25
You are right sir, I get information from nxp website, that card is smartMX. Thank you. – sams Dec 24 '15 at 22:53

External authentication in DESFire card with ISO 7816-4 APDUs

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