The Futures Contract has a unique hash derived from its parameters. There can be no two futures contracts with the same hash and different parameters as all parameters are included in the hash. A change in any parameter will result in a new futures contract hash.
bytes32 futuresContractHash = keccak256(
When a user places an order, the order is placed to trade a specific futures contract and the futures contract hash is embedded in the user’s signature. This way the user can be sure that he/she is trading the correct asset/futures contract.