According to the invention, techniques for verifying that data input as a response to presented contents is true input data for a content access. In a representative embodiment according to the present invention, there is provided an electronic authentication method that comprises a variety of steps, such as a step of generating an identifier for contents in a first information processing apparatus and storing the identifier in a storage unit. Transmitting the contents and the identifier to a second information processing apparatus can also be part of the method. Steps of inputting data for the contents in the second information processing apparatus and transmitting the input data and the identifier from the second information apparatus to the first information apparatus can also be included in the method. Further, the method can also include authenticating legitimacy of the input data and invalidating the stored identifier if the received identifier matches the identifier in the storage unit in the first information processing apparatus.