A smart contract can't tell whether a submitted score came from a valid game or was simply made up. Dario Dash handles that by proving the run itself.
I have been building Dario Dash, a small endless runner on Dusk. The game runs in the browser and does not require a wallet to play. After a ranked run, the browser can generate a Groth16 proof locally and submit the score to a smart contract.
The contract does not trust the submitted score. It accepts it only after verifying the proof, binding it to the transaction sender and checking that the run seed has not already been used.
The source is available on GitHub.
What actually needs to be proven?
