Document Type and Number:
Japanese Patent JP3147120
PROBLEM TO BE SOLVED: To realize a ciphering release of ciphered contents using simpler procedures by individually recording IDs, which are made different for every disk, a ciphering key for communication and a deciphering key for a deciphering ciphered sentence as required in an additional region during a manufacturing.
SOLUTION: In a password issuing center 821, a password generating section 834 generates a password based on three pieces of information, i.e., an ID, the contents number, which is desired to be deciphered by a user, and time information indicating the utilization approval period for the user and transmits the information to a first computer 909. In a second computer, information, in which a deciphering key disk ID that releases the cipher of n-th content and time information are mixed, is ciphered by an open key of an open key cipher, an n-th password 834a, in which a secret key that deciphers the ciphered information, is generated by the section 834 and transmitted to the computer 909. The computer 909 receives an n-th password and the disk LD, the time information and the deciphering key of the n-th content are deciphered by the secret key.
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January 12, 2001
October 08, 1996
MATSUSHITA ELECTRIC IND CO LTD
G11B7/24; G06F1/00; G06F12/14; G06F21/10; G06F21/24; G06K1/12; G06K19/04; G06K19/06; G06K19/08; G06K19/14; G11B7/0045; G11B7/005; G11B7/007; G11B7/26; G11B19/04; G11B19/12; G11B20/00; G11B20/10; G11B20/12; G11B23/00; G11B23/28; G11B23/30; G11B23/38; G11B27/24; G11B5/86; G11B7/00; G11B7/0037; G11B13/04; G11B20/14; G11B20/18; (IPC1-7): G11B20/10; G11B7/005