Ghost Map: Proving Software Correctness using Games

A large amount of intellectual effort is expended every day in the play of on-line games. It would be extremely valuable if one could create a system to harness this intellectual effort for practical purposes. In this paper, we discuss a new crowd-sourced, on-line game, called Ghost Map that presents players with arcade-style puzzles to solve. The puzzles in Ghost Map are generated from a formal analysis of the correctness of a software program. In our approach, a puzzle is generated for each potential flaw in the software and the crowd can produce a formal proof of the software’s correctness by solving all the corresponding puzzles. Creating a crowdsourced game entails many challenges, and we introduce some of the lessons we learned in designing and deploying our game, with an emphasis on the challenges in producing real-time client gameplay that interacts with a server-based verification engine. Finally, we discuss our planned next steps, including extending Ghost Map’s ability to handle more complex software and improving the game mechanics to enable players to bring additional skills and intuitions to bear on those more complex problems. Keywords-games; static analyses; formal verification; crowd souring; games; model checking.