A method and system for secured broadcasting of a digital data flow between a technical platform (1) and at least one terminal (2), characterized in that it comprises the following steps: transmitting a scrambled and multiplexed digital data flow with at least one message (ECM) including a control key (CW) encrypted by a channel key (CC); descrambling in a secured memory area of the terminal (2) the scrambled digital data flow from the control key (CW) obtained according to the following substeps; sending to the technical platform (1) a request including the identifier (IUi) of the terminal (2); generating a secret key (CSk) from a cryptographic mechanism (A) using a single ciphering key (BSKn) and the identifier (IUi) of the terminal (2) with view to ciphering said channel key (CC) and obtaining a message (eCCk); deciphering the message (eCCk) received by a terminal (2) from the key (CSk) initially stored in the terminal (2) so as to obtain the channel key (CC), and obtaining the control key (CW) resulting from the deciphering of the message (ECM) from the channel key (CC).