 
 byte KeyA_List_D3[][6] =
 {
-  { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },  // Sector 0
+  { 0xFF, 0xff, 0xff, 0xff, 0xff, 0xff },  // Sector 0
   { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },  // Sector 1
   { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },  // Sector 2
   { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },  // Sector 3

          // Starting of a new sector ... try to to authenticate
          Serial.print("------------------------Sector ");Serial.print(currentblock/4, DEC);Serial.println("-------------------------");
           Serial.print("keys used:");
           for (uint8_t i = 0; i < 5; i++)
           {
            Serial.print(" ");Serial.print(KeyA_List_D3[currentblock/4][i], HEX);
           }

           
          if (currentblock == 0)
          {
              success = nfc.mifareclassic_AuthenticateBlock (uid, uidLength, currentblock, 0, KeyA_List_D3[0]);
              
          }
          else
          {
              success = nfc.mifareclassic_AuthenticateBlock (uid, uidLength, currentblock, 0, KeyA_List_D3[currentblock/4]);
          }
          if (success)
          {
