image data , such as image data coded in mpeg4 format , is verified by a client receiving an information data stream that is generated by multiplexing a plurality of coded object data and associated intellectual property management data , from a contents distribution server , wherein the intellectual property management data includes source information representing a copyright holder of the object data . verification request data is transmitted , based on the source information included in the received intellectual property management data , to the copyright holder , via a different communication channel from that used for receiving the information data stream . the client receives , from the copyright holder , verification result data relating to the object data and then , a decoding process of the object data is controlled based on the verification result data .