Method and apparatus for writing and using keys for encrypting/decrypting a content and a recording medium storing keys written by the method

摘要

Content encryption information on content data recorded on a recording medium. A plurality of encryption keys used for encrypting a plurality of data clips containing content data is stored in a key file and index information for associating each of the plurality of encryption keys with a data segment encrypted with the encryption key is placed in the key file or in another management information file (e.g., clip information file). As a consequence, it is allowed to decrypt encrypted content data with different encryption keys by applying each of the plurality of encryption keys to each associated data segment.