Protocol for program during startup sequence

A system and a method to determine if a client (e.g., an accessory (or peripheral)) is appropriately licensed for interoperation with a host (e.g., host computer). The client communicatively couples the host and receives a contract from the host. The client computes a checksum of the contract and compares the checksum of the contract with a previously stored version of the contract or a checksum of the contract to determine a match. If there is no match, the host communicatively decouples the client in response to the determination being a no match. If there is a match, the client transmits a contract response to the host and awaits host authorization. Once authorized the client transmits enumeration data to the host.