Digital signal recording and playback apparatus

A digital signal recording and playback apparatus for recording an inputted digital signal to a recording medium, and for playing back the digital signal from the recording medium, the digital signal recording and playback apparatus comprising:

• a recording control module which controls recording of the digital signal to the recording medium;
• a playback control module which controls playback of the digital signal from the recording medium;
• an encryption module which encrypts the digital signal;
• a decryption module which decrypts the encrypted digital signal;
• and
• a control module which controls the recording control module, the encryption module, the decryption module, and the playback control module;
• wherein:
• a playback control flag relating to playback restrictions is added to the inputted digital signal;
• and
• the control module performs control so that digital signals are recorded to a first recording area and a second recording area on the recording medium, the first recording area storing an ordinary digital signal, the second recording area storing the digital signal including the added control flag after the digital signal is encrypted, the control module further performing control so that an encryption key of the digital signal recorded to the second recording area is erased under specified conditions.