Viaccess

Nicolas Pochon

Quentin Chieze

Mathieu Boivin

Mathieu Phirmis

Stephane Lafranchi

Stéphane Lafranchi

A Method for supplying protected multimedia content during which a terminal a) acquires a service date from a date server and b) evaluates a temporal criterion of a licence with respect to the last acquired service date. A headend associates with each segment of the multimedia content, its transmission date, and transmits it in a stream together with the segment. The terminal extracts from the stream the date of transmission of the segment, then it compares the extracted transmission date to the last acquired service date. And, only if the extracted transmission date is later than the last acquired service date, acquires it as service date, and uses it as last acquired service date on an execution of the step b) between two successive executions of the step a).

Method for supplying protected multimedia content to a terminal

Protecting data transmission, either multimedia or a control word, between a security processor and a terminal includes, at the security processor, building a current session key by root key diversification as a function of a parameter transmitted by the terminal, decrypting the data, encrypting it with the session key, and transmitting it, and at the terminal, decrypting it using a secret code to obtain plain data, recording, in advance, secret codes, each enabling decryption of only data encrypted by a corresponding session key obtained by root-key diversification with a parameter, which can be the transmitted parameter, receiving the parameter in a message that also contains the data to be decrypted by the security processor, and in response, selecting, from the secret codes, a code for decrypting the data encrypted with the session key, as a function of the parameter or another parameter in the message.

Growing community of inventors

Paris, France

Nicolas Pochon