Method of copying and decrypting encrypted digital data and apparatus therefor

A method of decrypting encrypted digital data stored in a second information storage medium in which a first media key block copied from a first information storage medium has been encrypted and recorded, the method comprising:

• (a) decrypting the encrypted first media key block using a first key of the second information storage medium;
• (b) obtaining a first media key from the decrypted first media key block using a second key of a device including the second information storage medium;
• and
• (c) decrypting the encrypted digital data using the first media key.

An apparatus for copying encrypted digital data stored in a first information storage medium to a second information storage medium, the apparatus comprising:

• a media key block encryption unit, which encrypts a first media key block to be used for decryption of the encrypted digital data using a predetermined key of the second information storage medium;
• and
• a data storage unit, which stores the encrypted digital data and the encrypted first media key block in the second information storage medium after the media key block encryption unit has encrypted the first media key block using the predetermined key of the second information storage medium,
• wherein the predetermined key of the second information storage medium is a second media key uniquely granted to the second information storage medium, and
• wherein the first media key block comprises a first encrypted media key, generated by encrypting a media key by a first device key, and a second encrypted media key, generated by encrypting the media key by a second device key.

An apparatus for decrypting encrypted digital data stored in a second information storage medium in which a first media key block copied from a first information storage medium has been encrypted and stored, the apparatus comprising:

• a first decryption unit, which decrypts the encrypted first media key block using a first key of the second information storage medium;
• a second decryption unit, which obtains a first media key from the decrypted first media key block using a second key of a device including the second information storage medium;
• and
• a third decryption unit, which decrypts the encrypted digital data using the first media key.

A Non-Transitory computer readable medium having recorded thereon a computer readable program for performing a method of decrypting encrypted digital data stored in a second information storage medium in which a first media key block copied from a first information storage medium has been encrypted and stored, the method comprising:

• (a) decrypting the encrypted first media key block using a first key of the second information storage medium;
• (b) obtaining a first media key by decrypting from the decrypted first media key block using a second key of a device including the second information storage medium;
• and
• (c) decrypting the encrypted digital data using the first media key.