Patent ID: 7466826

Claim:
A method for transmitting digital data representing a content from a source to a receiver through a digital communication channel, the digital data being scrambled by at least one control word, comprising the steps of: (a) generating an ephemeral encryption key stored temporarily by the source; (b) encrypting said control word using said encryption key; (c) transmitting to the receiver; the scrambled digital data; the encrypted control word, the latter being transmitted through an encrypted secure communication channel between the source and the receiver; and an authentication key: (d) after the transmission step, in response to the receipt of a random number, transmitting said encryption key with a result of calculation, based on said authentication key and said random number, to the receiver, where said receiver can decrypt said control word with said encryption key upon successful authentication; (e) erasing said encryption key in accordance with at least one transmission limitation associated with the digital data.