In transmission of stream data protected for copyright on a bus, transcription of stream data once recorded on a recording apparatus to a medium of another recording apparatus is realized. Authentication is carried out between a stream recording and playback apparatus and another recording apparatus to interchange a key for data scramble. By using this key, data is added with copy control information used when the data is recorded initially and thereafter the data is transmitted. After the data has been recorded on the recording apparatus, the data is deleted from an original recording medium. During transmission of the data, authentication from a different apparatus is rejected to prevent a plurality of copies from being made.