Provably fair raffle: proof you can verify

A provably fair raffle lets participants check that the outcome was not swapped after the rules were fixed. Integrity is not the same as unpredictability.

Core ingredients

• Locked rules — list, range and description published first
• List commit — SHA-256 of the canonical name list shared before the draw
• A seed nobody can grind — a future public beacon, not a clock the operator clicks
• Open binding — SHA-256 and rejection sampling anyone can re-run

How EntropyDraw implements it

Each draw creates /d/{id}, locks the rules, assigns the next drand round, then computes only after that round exists. Check SHA-256(signature) = randomness, recompute the v2 hash, and follow the on-page verification checklist.

Compared with traditional raffles

Physical draws are hard to audit remotely. Hidden-seed apps ask for trust. A commit-then-beacon flow gives remote proof that the winner was not selected by retrying inputs.

Best practices

Publish the list commit hash and the /d/{id} link at lock time, before the number exists. Archive the beacon round. For regulated contexts, confirm legal requirements separately — this is cryptographic transparency, not a license.