It's like Pokemón!

There is a referee server that all the clusters connect to. Each cluster can get a list of all the other clusters and their health. Attacks are performed by specifying the target cluster to the referee and receiving a hash. Reversing the hash successfully and sending the answer to the server will remove the hit points from the target. The clusters can also request a health boost from the referee server by solving similar hashes. There will also be a "golden egg" hash which is just really hard to solve. First one to get it automatically wins.