A locking and unlocking method executed by a portable terminal, the portable terminal including a service providing unit, a first sending unit, and a first receiving unit, the portable terminal configured to communicate with a first server configured to communicate with the portable terminal and store authentication information for locking or unlocking a vehicle or facilities in accordance with a use reservation of the vehicle or the facilities and a second server, different from the first server, configured to communicate with portable terminal and manage use reservation information of the use reservation of the vehicle or the facilities, the locking and unlocking method executed by the portable terminal comprising:
- providing, by the service providing unit, a use reservation service for making the use reservation of the vehicle or the facilities by communicating with the second server without going through the first server;
- sending, by the first sending unit, a first signal to the first server in response to a request from the service providing unit;
- and
- receiving, by the first receiving unit, the authentication information from the first server, wherein
- the first server that stores the authentication information for locking or unlocking the vehicle or the facilities in accordance with the use reservation of the vehicle or the facilities is administered by another organization different from an organization that administers the second server that manages the use reservation information of the use reservation of the vehicle or the facilities,
- the use reservation service is executed by an application program installed in the portable terminal, the application program being administered by the organization that administers the second server that manages the use reservation information of the use reservation of the vehicle or the facilities and that is different from the organization that administers the first server that stores the authentication information for locking or unlocking the vehicle or the facilities in accordance with the use reservation of the vehicle or the facilities, and
- the first signal is sent to the first server by the first sending unit when a user performs an operation on the portable terminal during execution of the application program that is administered by the second server.