(In)secure multimedia transmission over RTP

Multimedia encryption is an intensely discussed topic where numerous approaches have been proposed. However, the concrete application scenario and the applicable notion of security of many proposed approaches is mostly not stated precisely or even at all. In this work security notions and application scenarios for multimedia encryption are discussed and a previously proposed multimedia encryption approach, i.e., RTP-header encryption, is analysed with respect to these scenarios and notions. We show that this selective encryption approach is insecure for sensible settings and for all sensible notions of security. The analysis focuses on the RTP packetization of H.264:AVC.