Toys
PUBLIC RANDOMNESS / PRIVATE AGREEMENT
Cast the Lot
Lock the choices first. Let a future public beacon decide. Give everyone the same proof.
Write the proposal
These words personalize the proposal, but they do not create the security. The future beacon does that work.
Quick mode targets the next three-second round; network delivery and verification can add a few seconds. Choose 30 seconds or longer when people need time to save the fingerprint.
After you lock it, share the fingerprint before the beacon round arrives.
Verify a transcript
Paste any Cast the Lot transcript. This browser recomputes every hash, verifies the threshold signature, and derives the winner again.
How does this establish trust?
The proposal hash commits the group to its exact question, ordered choices, contributions, and future beacon round. Drand participants produce that round only later through threshold cryptography.
The app hashes the proposal and beacon randomness together, then uses rejection sampling to choose uniformly from the list. Anyone can replay those steps from the transcript.
The proof does not show that an organizer shared only one proposal. The group should save or acknowledge one fingerprint before the round arrives.
"The lot is cast into the lap, but its every decision is from the LORD." Proverbs 16:33