A content signal having a control signal added thereto indicating whether a playback
restricting function for restricting reproduction is activated is recorded on a
disk. When an encryption key generation section determines at the time of reproduction
that the content signal has the control signal added thereto indicating that the
playback restricting function is activated, it is determined whether a playback
permission condition is satisfied. The playback permission condition is read from
the disk, or acquired via a communication section if it is not stored on the disk.
A correct encryption key (Kp) is supplied to an encryption processing section only
when the playback permission condition is satisfied. The encryption processing
section decrypts the encrypted content signal recorded on the disk with the encryption
key (Kp) and the correctly decrypted content signal is outputted from an output
control section.