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Data management system

  • US 5,974,141 A
  • Filed: 10/18/1996
  • Issued: 10/26/1999
  • Est. Priority Date: 03/31/1995
  • Status: Expired due to Term
First Claim
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1. A system for managing digital data to be transferred from an owner of data to a user of data via a communication network, whereby:

  • secret-key, public-key, private-key, owner label, user label and data label are used in the data management system;

    a data management center is linked to a public-key storage and a secret-key generator and is arranged on said communication network;

    said data management center certifies public-keys of said owner and said user, and stores said owner label, said user label and said data label;

    said owner presents said owner label and data label, and requests a secret-key for data encryption to said data management center;

    said data management center prepares a data label fingerprint from said data label, and distributes secret-key for encryption which is encrypted by using said public-key of owner together with said data label fingerprint, to said owner;

    said owner encrypts the data using said secret-key which is decrypted by using private-key of said owner, and transfers said encrypted data, said data label and said data label fingerprint to a first user;

    said first user presents user label of said first user, said data label and said data label fingerprint, and requests a secret-key for decrypting said encrypted data and a secret-key for re-encrypting said data which is decrypted, to said data management center;

    said data management center confirms validity of said data label by said data label fingerprint, registers said user label of first user, and distributes said secret-key for decrypting encrypted data and said secret-key for re-encrypting decrypted data, both of which are encrypted by using the public-key of said first user to said first user; and

    said first user decrypts said secret-key for decryption and said secret-key for re-encryption by using the private-key of said first user, decrypts and uses the encrypted data using said secret-key for decryption, encrypts the decrypted data using said secret-key for re-encryption to be stored and copied, and transfers the encrypted data together with said data label, data label fingerprint and said user label of first user to the next user.

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