Quality-optimized and secure end-to-end authentication for media delivery

The need for security services, such as confidentiality and authentication, has become one of the major concerns in multimedia communication applications, such as video on demand and peer-to-peer content delivery. Conventional data authentication cannot be directly applied for streaming media when an unreliable channel is used and packet loss may occur. This paper begins by reviewing existing end-to-end media authentication schemes, which can be classified into stream-based and content-based techniques. We then motivate and describe how to design authentication schemes for multimedia delivery that exploit the unequal importance of different packets. By applying conventional cryptographic hashes and digital signatures to the media packets, the system security is similar to that achievable in conventional data security. However, instead of optimizing packet verification probability, we optimize the quality of the authenticated media, which is determined by the packets that are received and able to be decoded and authenticated. The quality of the authenticated media is optimized by allocating the authentication resources unequally across streamed packets based on their relative importance, thereby providing unequal authenticity protection. The effectiveness of this approach is demonstrated through experimental results on different media types (image and video), different compression standards (JPEG, JPEG2000, and H.264), and different channels (wired with packet erasures and wireless with bit errors).