A secure communication method is performed in a system including a terminal device and an authentication server. The terminal device has at least one service process supplying a service to other terminal devices and a user authentication process performing authentication of a user, which processes run on the terminal device. The authentication server has an encryption key of the service process, registered therein in advance. The secure communication method includes the steps of generating a secret key used for achieving secure communication between the service process and the user authentication process by the authentication server, the generation being performed independently of the user authentication process; and encrypting the generated secret key with the encryption key of the service process to transmit the encrypted secret key to the service process by the authentication server.