Data management system
First Claim
1. A method comprising:
- a computing device requesting data content from a data management center;
subsequent to said requesting data content, the computing device receiving from the data management center;
an encrypted version of a first message, wherein the first message comprises the requested data content and a first electronic watermark that includes information relating to a first user of the computing device; and
an encrypted first secret key;
the computing device decrypting the received encrypted version of the first message;
the computing device decrypting the received encrypted first secret key using a user key;
the computing device encrypting a second message using the decrypted first secret key, wherein the second message comprises the requested data content, the first electronic watermark, and a second electronic watermark that includes information relating to a second user that is different from the first user; and
the computing device sending information to the data management center that is usable by the data management center to confirm that the second user is allowed to receive the first secret key to decrypt the second message.
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Accused Products
Abstract
To prevent piracy or leakage of data content, a cryptography technique and electronic watermark technique are combined together and used. In a data content supplied to a user, a user data is entered as electronic watermark by a data management center, and the data content with an electronic watermark entered in it is encrypted using a crypt key and is supplied. The encrypted data content is decrypted using a crypt key distributed from the data management center and is used. In case it is to be stored, it is encrypted using another crypt key. In case the data content is copied and transferred to other user, a user data of the other user is entered as electronic watermark, and a scenario to enter the user data of the other user as electronic watermark is registered at the data management center, and the data content with electronic watermark entered in it is encrypted using another crypt key and is supplied. When the validity of the other user is confirmed by the scenario, another crypt key is distributed to the other user. The encrypted data content is decrypted using another crypt key and is used. When it is to be stored, it is encrypted using still another key. In case the data content has been copied and transferred illegitimately, it is possible by verifying the electronic watermark to identify the user who has copied and transferred the data content illegitimately.
300 Citations
22 Claims
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1. A method comprising:
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a computing device requesting data content from a data management center; subsequent to said requesting data content, the computing device receiving from the data management center; an encrypted version of a first message, wherein the first message comprises the requested data content and a first electronic watermark that includes information relating to a first user of the computing device; and an encrypted first secret key; the computing device decrypting the received encrypted version of the first message; the computing device decrypting the received encrypted first secret key using a user key; the computing device encrypting a second message using the decrypted first secret key, wherein the second message comprises the requested data content, the first electronic watermark, and a second electronic watermark that includes information relating to a second user that is different from the first user; and the computing device sending information to the data management center that is usable by the data management center to confirm that the second user is allowed to receive the first secret key to decrypt the second message. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus, comprising:
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means for requesting data content from a data management center; means for receiving, from the data management center, an encrypted version of a first message, wherein the first message comprises; the requested data content; a first electronic watermark that includes information relating to a first user of the computing device; and an encrypted first secret key; means for decrypting the encrypted version of the first message; means for decrypting the encrypted first secret key using a user key; means for encrypting a second message using the decrypted first secret key, wherein the second message comprises the requested data content, the first electronic watermark, and a second electronic watermark that includes information relating to a second user that is different from the first user; and means for sending information to the data management center that is usable by the data management center to confirm that the second user is allowed to receive the first secret key to decrypt the second message. - View Dependent Claims (7, 8, 9, 10)
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11. A system comprising:
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a microprocessor; and memory, coupled to the microprocessor, storing program instructions that are executable by the system to cause the system to perform operations comprising; requesting data content from a data management center; subsequent to said requesting data content, receiving from the data management center; an encrypted version of a first message, wherein the first message comprises the requested data content and a first electronic watermark that includes information relating to a first user of the computing device; and an encrypted first secret key; decrypting the received encrypted version of the first message; decrypting the received encrypted first secret key using a user key; encrypting a second message using the decrypted first secret key, wherein the second message comprises the requested data content, the first electronic watermark, and a second electronic watermark that includes information relating to a second user that is different from the first user; and sending information to the data management center that is usable by the data management center to confirm that the second user is allowed to receive the first secret key to decrypt the second message. - View Dependent Claims (12, 13, 14, 15, 16)
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17. An article of manufacture including a computer-readable medium having instructions stored thereon that, in response to execution by a computing device, cause the computing device to perform operations comprising:
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requesting data content from a data management center; subsequent to said requesting data content, receiving from the data management center; an encrypted version of a first message, wherein the first message comprises the requested data content and a first electronic watermark that includes information relating to a first user of the computing device; and an encrypted first secret key; decrypting the received encrypted version of the first message; decrypting the received encrypted first secret key using a user key; encrypting a second message using the decrypted first secret key, wherein the second message comprises the requested data content, the first electronic watermark, and a second electronic watermark that includes information relating to a second user that is different from the first user; and sending information to the data management center that is usable by the data management center to confirm that the second user is allowed to receive the first secret key to decrypt the second message. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification