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US 8,265,271 B2Granted
Method and device for managing a transmission of keys
AssigneeThomson Licensing
InventorsMohamed Karroumi, Stephane Onno, Alain Durand
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AssigneeThomson Licensing
InventorsMohamed Karroumi, Stephane Onno, Alain Durand
Estimating the term…
The present invention concerns a method and a device for encrypting an encoded scalable enhancement frame sent by an emitter to a receiver, the enhancement frame comprising a plurality of complementary streams ordered in term of quality level, each complementary stream corresponding to a combination of more than one scalability type, where a complementary stream of a lower quality level corresponds to a lower quality on each scalability type, comprising at the level of the emitter the steps of generating a key per complementary stream for encrypting said complementary stream in such a way that all scalability types can be either simultaneously or individually used, said keys being generated in such a way that only the keys of the complementary streams of quality levels lower than the quality level of a complementary stream can be obtained from the key of said complementary stream, and sending the key of a complementary stream corresponding to a required quality level to the receiver, the key permitting a receiver to generate the keys of the complementary streams of the lower quality levels only. The present invention also concerns a method and a device for decrypting a received encoded scalable enhancement frame.
A method for encrypting an encoded scalable enhancement frame sent by a sender device via its communicating means to a receiver device over a communications network, said encoded scalable enhancement frame comprising a plurality of complementary streams ordered in term of quality level, each complementary stream corresponding to a combination of more than one scalability type, where a complementary stream of a lower quality level corresponds to a lower quality on each scalability type, said method comprising:
A method for calculating decryption keys intended to decrypt an encoded scalable enhancement frame received by a receiver device via its communicating means from a sender device over a communications network, said enhancement frame comprising a plurality of complementary streams ordered in term of quality level, each complementary stream corresponding to a combination of more than one scalability type, where a complementary stream of a lower quality level corresponds to a lower quality on each scalability type, said method comprising:
A device for encrypting an encoded scalable enhancement frame comprising a plurality of complementary streams ordered in term of quality level, each complementary stream corresponding to a combination of more than one scalability type, where a complementary stream of a lower quality level corresponds to a lower quality on each scalability type, said device comprising encrypting means for generating one random key (KM,T) corresponding to a key of the complementary stream of the higher quality level (SM,T), for generating keys of the complementary streams of the lower quality levels by successively applying a one-way function to the random key (KM,T), where the one-way function output is different for each scalability type, and communicating means for sending a key of a complementary stream corresponding to a quality level to a receiver device over a communications network,
A device for decrypting an encoded scalable enhancement frame comprising a plurality of complementary streams ordered in term of quality level, each complementary stream corresponding to a combination of more than one scalability type, where a complementary stream of a lower quality level corresponds to a lower quality on each scalability type, said device comprising decrypting means for generating, from a received key (Km,t), subsequent keys of the complementary streams corresponding to the lower quality levels only by successively applying a one-way function (h) to the received key, where the one-way function output is different for each scalability type, and communicating means for receiving a key over a communications network,
Dependencies are inferred from the claim text.