Abstract: A system for executing personal authentication processing by communication through a human body, in which authentication corresponding to a service to be furnished can be executed efficiently. The authentication processing between a portable equipment worn by a user and a service furnishing terminal is executed by a human body touching a contact point of the service furnishing terminal. The processing occurs with a real physical feeling of user contact. A user-native identifier and a user-variable identifier generated from user to user depending on the service presented by a service terminal are stored in a user equipment. Responsive to the service identifier transmitted from the service terminal, service-native user identification data, derived at least from the user variable identifier, is generated in the portable equipment and forwarded to the service terminal. A variety of user management operations, such as user-based assessment operations, depending on service contents, are carried out.