In Derivatives Trading, How Does the Concept of a “Key” Translate to Asset Control?

While derivatives are often centralized, the concept translates to control over the collateral or margin. In decentralized derivatives (DeFi), control is maintained via smart contracts, where the "key" is the private key controlling the wallet interacting with the contract.

For centralized derivatives, the "key" is the access credential to the brokerage account, but the ultimate asset control rests with the broker, similar to an exchange holding crypto keys.