fix incorrect data of IDx in getPuKxRx()

src/main/java/com/josh/vku2f/CTAP2.java

@@ -378,8 +378,9 @@ public class CTAP2 extends Applet implements ExtendedLength {
      * return: PuKx and Rx in CBOR form
      */
     private void getPuKxRx(APDU apdu, short dataLength){
-        // TODO IDx have to get data from dataBuffer at index 1
-        idSecret.IDx = new DomString(dataBuffer, dataLength);
+        // Done IDx have to get data from dataBuffer at index 1
+        Util.arrayCopy(dataBuffer, (short)1, scratch, (short)0, (short)(dataLength-1));
+        idSecret.IDx = new DomString(scratch, (short)(dataLength-1) );
         cborEncoder.init(dataBuffer, (short) 0, (short)1200);
         cborEncoder.startArray((short)2);
         cborEncoder.encodeUInt32(idSecret.Rx, (short)0);