The oracle generates a random secret and submits sha256(secret + oracle_pubkey) on-chain as a commitment — before you pay anything.

You pay and lock in the commitment with your own random user seed — the oracle doesn't know this seed yet, so it can't manipulate your outcome.

The oracle reveals its secret. The contract verifies sha256(secret + oracle_pubkey) matches the commitment stored on-chain. If it doesn't match, the transaction fails.

Traits are derived from sha256(secret + slot_hash + user_seed). Neither the oracle (didn't know user_seed) nor you (didn't know secret or slot_hash) could predict or manipulate the result.