# Futures Contract

On [DMEX](https://dmex.app/?utm_source=medium\&utm_medium=story\&utm_campaign=part1), users trade futures contracts. Futures contracts are defined by the following parameters:

| Parameter         | Type    | Description                                                                                                                                                                |
| ----------------- | ------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| asset             | bytes32 | the hash of the underlying [asset object](https://docs.dmex.app/definitions/asset-definitions)                                                                             |
| expirationBlock   | uint256 | futures contract expiration block                                                                                                                                          |
| closingPrice      | uint256 | the closing price for the futures contract                                                                                                                                 |
| closed            | bool    | is the futures contract closed? (0 - false, 1 - true)                                                                                                                      |
| broken            | bool    | if someone has forced release of funds after no settlement for two hours, the contract is marked as broken and can no longer close positions, all collaterals are released |
| multiplier        | uint256 | the multiplier price (usually 1/ETHUSD x 1e8)                                                                                                                              |
| fundingRate       | uint256 | funding rate expressed per block \* 1e18                                                                                                                                   |
| closingBlock      | uint256 | the block in which the contract was closed (0 while contract open)                                                                                                         |
| perpetual         | bool    | true if the contract is perpetual                                                                                                                                          |
| maintenanceMargin | uint256 | the maintenance margin coefficient                                                                                                                                         |

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.

```javascript
bytes32 futuresContractHash = keccak256(
    this, 
    asset, 
    expirationBlock, 
    multiplier, 
    fundingRate, 
    perpetual, 
    maintenanceMargin
);
```

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.