How to find whether an Android stack in phone is Original or Jail-broken?

I would like to know how to find whether an Android stack in phone is Original or Jail-broken?

My Intention :
My application will check for the genuineness of the Android OS in phone.
If it finds that, the phone does not have a genuine Android, it will not allow the application to install on phone.

Is it possible to implement this?

Thanks,
Sen

Solution

Check if you can "su" on the phone with an installer application. If you can't, install your apk as you please.