crack/hack an small iOS app for me

I have small iOS app . 1. It run require key. 2. it can only run in 1 device at 1 time . if i open 2 app instance in 2 device A & B . A is fine . But when open app in Device B . preview app on device A is closed I know this is the simple task for cracker/hacker I want to find a long-term friend do to more other task . So only bid if you can do this I will upload app for bidder Thanks you