Provably-fair draws without an expensive on-chain VRF

If you run a raffle, an airdrop allocation, a grant lottery or a jury selection, you eventually need to prove it was fair. On-chain VRFs work but cost gas and add a smart-contract dependency. And every certificate signed with classical crypto becomes forgeable in the quantum era — a problem for anything that must hold up for years.

There is a simpler, verifiable approach. Commit publicly, before the draw, to (1) the exact participant list (its hash) and (2) a FUTURE round of a public randomness beacon (the League of Entropy / drand publishes a new value every ~30s). The randomness of a future round does not exist yet — nobody, including you, can know or rig it.

When the round publishes, derive the winners deterministically from its public value, and sign the certificate post-quantum (Dilithium-2). Anyone re-derives the winners from the public drand value and checks the signature — no trust in you required, off-chain, $0 gas.

Honest scope: this proves the result was unpredictable and unaltered. It does NOT prove your participant list was complete (publish the commitment beforehand to address that). Not "unbreakable" — depends on drand integrity and known-secure crypto. Try a 50-entry draw in your browser.