System and methods for transmitting encrypted data with encryption key

摘要

The present invention relates to a method for transmitting information between a transmitter station (100e) and a plurality of receiving stations (100r) wherein encrypted information is transmitted from the transmitter station to the receiver station with a first key and at least a control message bearing a second key. According to the invention, the first key used for decryption is restored in each receiving station from the second key and from at least one datum selected from a set of data available in the receiving stations, according to a selection command periodically transmitted between the transmitting station and the receiving station. Application to pay television.