A mobile telephone serving as a first apparatus enters image data with stegano data embedded, that cannot be recognized visually, the mobile telephone sending the entered image data to the outside and receiving the result of processing from the outside, for holding the same. A server acting as a second apparatus effects data processing on the image data received from the mobile telephone, to acquire stegano data, and sends the acquired stegano data as the result of processing to the mobile telephone. Being the mobile telephone with a camera having a limited processing performance, the first apparatus sends image data with stegano data embedded to the second apparatus, such as the server, having a high processing capability and being connected to the first apparatus through a communication path, in order to acquire the result of processing.