Provably-Fair Verifier

Recompute any round locally. Nothing is sent to a server.

Operator IDRevealed Server SeedClient SeedNonceExpected Digest (from round result)

Formula: HMAC_SHA256(serverSeed, `${operatorId}:${clientSeed}:${nonce}`). The serverSeedHash you saw before the round must match SHA-256 of the revealed seed.