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AndroidCrypto · Aug 29, 2024 · a1dc71d · a1dc71d
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commit a1dc71d
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diff --git a/README.md b/README.md
@@ -81,6 +81,13 @@ Minimum SDK is 21 (Android 5)
 
 The Ultralight C tag uses a Triple DES authentication scheme with a 2 DES keys model, so in the end it uses a 16 bytes long TDES key. 
 
+I'm using 2 predefined keys in the app:
+
+```plaintext
+byte[] defaultAuthKey = hexStringToByteArray("49454D4B41455242214E4143554F5946"); // "IEMKAERB!NACUOYF" => "BREAKMEIFYOUCAN!", 16 bytes long
+byte[] customAuthKey = "1234567890123456".getBytes(StandardCharsets.UTF_8);
+```
+
 ### Counter on Mifare Ultralight-C:
 ```plaintext
 7.5.11 Counter

diff --git a/app/src/main/java/de/androidcrypto/mifare_ultralight_c_explorer/MIFARE_Ultralight_C.java b/app/src/main/java/de/androidcrypto/mifare_ultralight_c_explorer/MIFARE_Ultralight_C.java
@@ -57,7 +57,6 @@ public class MIFARE_Ultralight_C {
 
     public static final byte[] defaultAuthKey = hexStringToByteArray("49454D4B41455242214E4143554F5946"); // "IEMKAERB!NACUOYF" => "BREAKMEIFYOUCAN!", 16 bytes long
     public static final byte[] customAuthKey = "1234567890123456".getBytes(StandardCharsets.UTF_8);
-    public static final byte[] default2AuthKey = "BREAKMEIFYOUCAN!".getBytes(StandardCharsets.UTF_8);
 
     public static boolean identifyUltralightFamily(NfcA nfcA) {
         // get card details
@@ -92,15 +91,12 @@ public static boolean authenticateUltralightC(NfcA nfcA, byte[] key) {
             byte[] rndA = new byte[8];
             generateRandom(rndA);
             Log.d(TAG, " - RndA: " + bytesToHexNpe(rndA));
-            //byte[] encRndArotPrime = transmitRaw(ArrayUtils.addAll(new byte[] {(byte) 0xAF}, desEncrypt(key, ArrayUtils.addAll(rndA, rndBrot))));
-            //byte[] rndARndBrot = ArrayUtils.addAll(rndA, rndBrot);
             byte[] rndARndBrot = combineByteArrays(rndA, rndBrot);
-            Log.d(TAG, printData("rndARndBrot", rndARndBrot));
+            Log.d(TAG, " - rndARndBrot: " + bytesToHexNpe(rndARndBrot));
             byte[] encRndARndBrot = desEncrypt(key, rndARndBrot);
-            Log.d(TAG, printData("encRndARndBrot", encRndARndBrot));
+            Log.d(TAG, " - encRndARndBrot: " + bytesToHexNpe(encRndARndBrot));
             byte[] dataToSend = combineByteArrays(new byte[]{(byte) 0xAF}, encRndARndBrot);
-            Log.d(TAG, printData("dataToSend", dataToSend));
-            // AF0A638559FC7737F9F15D7862EBBE967A
+            Log.d(TAG, " - dataToSend: " + bytesToHexNpe(dataToSend));
             byte[] encRndArotPrime;
             try {
                 encRndArotPrime = nfcA.transceive(dataToSend);
@@ -110,15 +106,15 @@ public static boolean authenticateUltralightC(NfcA nfcA, byte[] key) {
             }
             Log.d(TAG, "encRndArotPrime: " + bytesToHexNpe(encRndArotPrime));
             if ((encRndArotPrime.length != 9) || (encRndArotPrime[0] != 0x00)) {
-                Log.d(TAG, "RuntimeException (Invalid response!)");
+                Log.e(TAG, "RuntimeException (Invalid response!)");
                 return false;
             }
             encRndArotPrime = Arrays.copyOfRange(encRndArotPrime, 1, 9);
             Log.d(TAG, " - EncRndArot': " + bytesToHexNpe(encRndArotPrime));
             byte[] rndArotPrime = desDecrypt(key, encRndArotPrime);
             Log.d(TAG, " - RndArot': " + bytesToHexNpe(rndArotPrime));
             if (!Arrays.equals(rotateLeft(rndA), rndArotPrime)) {
-                Log.d(TAG, "RuntimeException (Card authentication failed)");
+                Log.e(TAG, "RuntimeException (Card authentication failed)");
                 return false;
             } else {
                 Log.d(TAG, "Card authentication success");