Process for reinforcing the security of a pay television system based on periodic mandatory back-communication

A process for transmitting streaming digital content on an Internet data communication network, said Internet network being structured according to a multi-broadcasting routing mode, said process being implemented by a digital content transmission system comprising:

• a digital rights management device (12, 13) including:
• at least one digital content encryption module (121, 122;
• 42), connected to a streaming digital content source (111) via said Internet data communication network;
• a module (124) for storing cryptographic encryption keys and content identifiers, connected to the encryption module (121, 122);
• a client device (14) for accessing said streaming digital content, connected to the digital rights management device (12, 13) via said Internet data communication network, and including:
• a module (141) for access, browsing and display of said streaming digital content;
• a client module (142) for digital rights management, connected to the module (141) for access, browsing and display of said streaming digital content;
• each module (121-124, 141-142, 42) being formed by a software component, a hardware component, or a set of hardware and software components;
• the process including the following steps:
• the transmission to the encryption module (121, 122;
• 42) of digital content, by the digital content source (111), of streaming digital content (31), via the Internet data communication network;
• the encryption, by the digital content encryption module (121, 122;
• 42), of said digital content (31) via a secret cryptographic encryption key;
• the determination, by the digital content encryption module (121, 122;
• 42), if the client device (14) has previously transmitted to the encryption module (121, 122;
• 42) the value of a variable representative of a state of the client device (14);
• and, depending on the particular case, the comparison, by the digital content encryption module (121, 122;
• 42), between the current value and preceding value of said variable, then the determination, by the encryption module (121, 122;
• 42), of a level of similarity between the current value and the preceding value of said variable;
• if, on completion of the step of determining a level of similarity, the encryption module (121, 122;
• 42) determines that the level of similarity is greater than a predetermined threshold level:
• the transmission to the cryptographic encryption key and content identifier storage module (124), by the digital content encryption module (121, 122;
• 42), of access criteria required for a given channel, said channel containing all or some of said digital content;
• the translation, by the cryptographic encryption key and content identifier storage module (124), of said required access criteria in the form of a specific content identifier and a specific content key;
• the transmission to the digital content encryption module (121, 122;
• 42), by the cryptographic encryption key and content identifier storage module (124), of said specific content identifier and said specific content key;
• the insertion, by the digital content encryption module (121, 122;
• 42), of said specific content identifier and said specific content key, in the encrypted digital content, a multiplexed data stream (34, 35) being obtained upon completion of this insertion step, the multiplexed data stream (34, 35) containing said encrypted digital content, said specific content identifier and said specific content key;
• the transmission to the module for access, browsing and display (141) of the client device (14), by the digital content encryption module (121, 122;
• 42), of said multiplexed data stream (34, 35) via said Internet data communication network;
• the recovery, by the module for access, browsing, and display (141), of the specific content identifier contained in the multiplexed data stream (34, 35), and the transmission of said digital content identifier to the client digital rights management module (142);
• the verification, by the client digital rights management module (142), if an object corresponding to said specific content identifier exists, and, depending on the particular case, the delivery of a right to access, browse, and display digital content to the access, browsing and display module (141).