<string name="select_slot">Select Slot</string>
        <string name="slot_1">Slot 1</string>
        <string name="slot_2">Slot 2</string>
+       <string name="need_slot">You must select which slot to use</string>
        <string name="enrollresult">Enrollment result:</string>
+       <string name="enroll_success">Token successfully bound to the device</string>
        <string name="challenging">Ready to send challenge</string>
-       <string name="swipe">Please touch the token with the phone</string>
+       <string name="swipe">Please touch the back of the phone with the NFC token to enroll it</string>
        <string name="no_nfc">Cannot reach the NFC adapter</string>
        <string name="nfc_disabled">Need to enable NFC in Settings</string>
        <string name="tag_lost">Communitation with the tag lost</string>
 
                        Toast.makeText(this, R.string.no_nfc,
                                                Toast.LENGTH_LONG).show();
                        finish();
-                       return;
                }
                if (! adapter.isEnabled()) {
                        Toast.makeText(this, R.string.nfc_disabled,
                                                Toast.LENGTH_LONG).show();
                        finish();
-                       return;
                }
                adapter.enableForegroundDispatch(
                        this, tagIntent, new IntentFilter[] {iso},
 
                if (slot > 0) {
                        runEnrollment(slot);
                } else {
-                       showEnrollResult("Must specify which slot to use");
+                       showEnrollResult(R.string.need_slot);
                }
        }
 
                editor.putString("challenge", hex(challenge));
                editor.putString("response", hex(response));
                editor.commit();
+               showEnrollResult(R.string.enroll_success);
                Log.v(TAG, "stored new challenge and response");
        }
 
-       private void showEnrollResult(final String msg) {
-               Log.v(TAG, "Show result: \"" + msg + "\"");
-
+       private void showEnrollResult(int messageid) {
                AlertDialog.Builder builder = new AlertDialog.Builder(this);
                builder.setTitle(R.string.enrollresult);
-               builder.setMessage(msg);
+               builder.setMessage(messageid);
                builder.setPositiveButton(android.R.string.ok,
                                new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int which) {
 
                                throw new CRException(
                                "NFC Error code in the response to CR");
                        }
+                       if (length != 22) {
+                               throw new CRException(
+                               "NFC wrong response size: " + (length-2));
+                       }
                        return Arrays.copyOf(resp, length-2);
                } catch (TagLostException e) {
                        throw new CRException("NFC connection lost", e);