To provide a content playback device capable of protecting content according to DRM, when decrypting encrypted content recorded on a recording medium and playing the decrypted content. If key generation information is "00", a key control unit 104 concatenates a decrypted media key and content information in this order, and applies a one-way function to the concatenation result to generate a content key. If the key generation information is "10", the key control unit 104 sets a rights key as the content key. If the key generation information is "01", the key control unit 104 concatenates the decrypted media key and the rights key in this order, and applies a one-way function to the concatenation result to generate the content key.