# 1337 Skills```App: https://play.google.com/store/apps/details?id=com.progressio.wildskillsConnection: nc 88.198.154.132 7002```
This is an Android reversing challenge. We can download the [apk here.](https://apkpure.com/es/wild-skills/com.progressio.wildskills)The app request an activation code to start using it. Let's dissasembly the apk in other to get those codes.
## JADX
Let's open the apk with [jadx.](https://github.com/skylot/jadx)In the **MainActivity** we see this function:```javapublic void activateApp(View view) {    int i;    try {        i = Integer.parseInt(this.editTextActivation.getText().toString());    } catch (NumberFormatException unused) {        i = -1;    }    Calendar instance = Calendar.getInstance();    if (i == ((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d))) {        findViewById(R.id.scrollViewActivation).setVisibility(4);        ((InputMethodManager) getSystemService("input_method")).hideSoftInputFromWindow(this.editTextActivation.getWindowToken(), 0);        SharedPreferences.Editor edit = this.prefsmain.edit();        edit.putBoolean("Activated", true);        long time = new Date().getTime();        edit.putLong("Installed", time);        edit.putLong("ActivationDate", time);        edit.commit();        return;    }    Toast.makeText(this, "Ungültiger Aktivierungscode", 1).show();    this.editTextActivation.requestFocus();    ((InputMethodManager) getSystemService("input_method")).showSoftInput(this.editTextActivation, 1);}```> Activation Code: `((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d))`
We can decode it with this code:```javaimport java.util.Calendar;
class Solver{      public static void main(String args[]){        Calendar instance = Calendar.getInstance();        System.out.printf("Activation Code: %d\n", ((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d)));      }}``````bash» javac sol.java» java SolverActivation Code: 76429```
Now we get the rest of codes in the function `courseActivation(View view)`:```java[...]if (obj.equals("sgk258"))[...]if (obj.equals("wmt275"))[...]if (obj.equals("udh736"))[...]```
Now, let's get the flag:```bash» nc 88.198.154.132 7002Activation code:76429activated!Sales activation code:sgk258activated!Leadership activation code:wmt275activatedService Roadmap (SRM) activation code:udh736activated!Congratulations please give me your name:Manu   ______________________________ / \                             \.|   |                            |. \_ |                            |.    | Certificate of Attendance  |.    |                            |.    |  This is to certify that   |.    |                            |.    |            Manu            |.    |                            |.    |        has attended        |.    |                            |.    | **The baby rev challenge** |.    |                            |.    |                            |.    |                       hxp  |.    |                            |.    | -------------------------- |.    |                            |.    |hxp{thx_f0r_4773nd1n6_70d4y}|.    |                            |.    |   _________________________|___    |  /                            /.    \_/____________________________/.
```