In the demo above, the moment you commit (Roll-Dice) a commit with the hash of a player secret is sent to the server and the server accepts that and sends back the hash of its secret back and the "future" drand round number at which the randomness will resolve. The future used in the demo is 10 secs

When the reveal happens (after drand's particular round) all the secrets are revealed and the random number is generated using "player-seed:server-seed:drand-signature".

All the verification is in Math, so truly trust-less, so:

1. Player-Seed should matches the player-hash committed

2. Server-Seed should matches the server-hash committed

3. Drand-Signature can is publicly not available at the time of commit and is available at the time of reveal. (Time-Locked)

4. Random number generated is deterministic after the event and unknown and unpredictably before the event.

5. No party can influence the final outcome, specially no "last-look" advantange for anyone.

I think this should be used in all games, online lottery/gambling and other systems which want to be fair by design not by trust.