Telediffusion De France

France Telecom

France Telecom Etablissement Autonome De Droit Public

France Telecom Establissement Autonome De Droit Public

Telediffusion

Francoise Coutrot

Pierre Fevrier

Jean-Luc Giachetti

Process for the transmission and reception of conditional access programs controlled by the same operator. According to the invention, specific check words (MCSi) are formed for various programs of the same operator from a root check word individual to said operator. The check words of the access titles include a part which is common to all the programs controlled by the same operator and a part which is specific to each program. Uses in television, radio, data transmission, messaging, etc.

Process for the transmission and reception of conditional access

A process for the transmission and reception of scrambled conditional access programs, which are synchronously transmitted with entitlement control messages (ECM), with a reduced program switching time. The entitlement control messages (ECM) have check words, which are changed after a period of time called a phase, for descrambling the conditional access programs. The process includes transmitting main check messages (ECMp) for a main access program at a first frequency (Fp) and transmitting secondary check messages (ECMs) for secondary programs at a lower, second frequency (Fs). The secondary check messages (ECMs) are transmitted between two successive transmission of the main check messages (ECMp) such that all of the secondary check messages (ECMs) for each of the secondary programs are transmitted in a single phase. Therefore, a check word for any program is quickly acquired and program switching time is reduced.

A process for the transmission and reception of personalized programs. The program is constituted by personalized program elements containing an identification of the recipient or addressee, the access to each program element being reserved for a single recipient and is conditioned for the possession of an access title covering the access criteria to the service and the possession of an individual identification on the part of each recipient. The access title control message enables users of the service to calculate, on the basis of the single cryptogram of a root control word and the identification of the recipient, all the personalized control words which will enable each recipient and him alone to descramble the elements relating to him.

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Cesson Sevigne, France

Francoise Coutrot