An authentication control device includes one or more memories, and one or more processors coupled to the one or more memories and the one or more processor configured to perform storing of a first authentication key received from a server device in the one or more memories, the first authentication key relating to a second authentication key stored in a terminal of a user, in communication between the authentication control device and the terminal in the state where the authentication control device is uncommunicable with the server device, in response to receiving, from the terminal, first information encoded in accordance with the second authentication key, perform decoding of the first information by the stored first authentication key, and execute an authentication process of the user in accordance with second information acquired by the decoding.