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US 2004/0202331 A1Published application
Method for controlling access to an encrypted programme
AssigneeNagra Thomson Licensing
InventorOdile Derouet
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AssigneeNagra Thomson Licensing
InventorOdile Derouet
Estimating the term…
This invention relates to an access control method for an encrypted program transmitted by an operator to a plurality of groups of subscribers, each group of subscribers being issued with a group key KG, and each subscriber being able to receive from the operator an operating key KT, enciphered by to the group key KG, for decryption of the transmitted program. The method according to the invention further comprises the following steps: Prior to transmission of the encrypted program, a—linking the enciphered operating key KT to a random value R to generate a secret code; b—transmitting the secret code to subscribers, c—transmitting the random value R to subscribers for calculation of the operating key KT, when the encrypted program is transmitted.
Access control method for an encrypted program transmitted by an operator (1) to a plurality of groups of subscribers, each group of subscribers having a group key KG, and each subscriber being able to receive from the operator (1) an operating key KT, enciphered by the group key KG for decryption of the transmitted program, a method further characterised by the inclusion of the following steps:
Access control method for an encrypted program transmitted by an operator (1) to a number of groups of subscribers, each group of subscribers being issued with a group key KG, and each subscriber being able to receive from the operator (1) a whole number m of operating keys KTi, for decryption of the program transmitted,
Dependencies are inferred from the claim text.