A processing method of content intended for broadcasting is disclosed. The method includes, preceding broadcasting: encryption of the content by a plurality of control words, reservation of locations intended to receive a control message in the encrypted content, marking of each location with location information in the content, and storage of a key file comprising the control words. During broadcasting, the method includes: transmission of the encrypted content to a video server, transmission of the key file to a control message generator, broadcasting of the content encrypted by the video server, interception of the video server output by a replacement module, detection, by the replacement module, of location information of control messages in the stream of the broadcasted content, and application of the control messages at locations provided for this purpose by the replacement module.