A contents recording and reproducing apparatus performs a record and a reproduce of a recording medium, in which the recording medium records a title key file registering therein at least one title key which encrypts each of plural title contents corresponding to a program video or sound, and title contents encrypted by the title key. The contents recording and reproducing apparatus includes an TKF initializing unit 141 which generates a title key file and records it in the recording medium, a random number generating unit 111 which generates a random number corresponding to each of the plural title key files, and a recording unit 113 which records a plurality of title key files in a DVD medium 140. The TKF initializing unit 141 registers the random number, the TKF random number corresponding to the title key file, and an encryption title key.