AUTHENTICATION SYSTEM, AUTHENTICATION METHOD, AUTHENTICATION DEVICE, INFORMATION TERMINAL, PROGRAM AND INFORMATION RECORDING MEDIUM

It is determined whether or not a subject operating an information terminal is a human without requiring a character input. A client device displays an authentication screen, sequentially acquires positional information on the authentication screen based on operation information which has been received, records a path which is indicated by the sequentially acquired positional information, and transmits the recorded path to an authentication server. The authentication server determines whether or not an operation indicated by the operation information is an operation performed by a human based on a fluctuation amount of the recorded path with respect to a path as a reference which is defined on the authentication screen.