To transmit digital data representing a content from a source to a receiver through a digital communication channel, the data being scrambled by at least one control word, the method includes the following steps. The source generates an encryption key which it stores temporarily. It encrypts the control word with the encryption key and transmits to the receiver the scrambled digital data and the encrypted control word, the latter being transmitted through an encrypted communication channel. The receiver then performs an operation of authentication of the source. When the source is authenticated by the receiver, it transmits the encryption key to it. The receiver then decrypts the control word and descrambles the data so as to present them to a user. The encryption key is then erased from the memories of the source and the receiver when the content has been entirely transmitted.