Humans and the Cheela work out a pact so the Cheela work as a computer for the humans.
Got a problem? Send it to the Cheela. They'll design your home, work out a complex math problem or tackle any mundane thinking job. Even if no one really wants to work on your problem, in the space of a human day generations of Cheela come and go and someone will pick it up and have a go in their spare time. They'll post it to their internet and some Cheela geek with nothing better to do will give it a shot.
- Of course if your original request gets misplaced by the time you ask about it a week later, millennia will have passed by...
Humanity is handed the encryption codes before long.
It was just a bunch of Cheela in power who decided to force the humans to work for stuff. Give the Cheela two hours and the political clime will change or some radical-human-loving fringe group will send it to us.