Fast protection of H.264/AVC by selective encryption of CABAC for I & P frames

This paper presents a novel method for the protection of copyrighted multimedia content. The problem of selective encryption (SE) is being addressed along with the compression for the state of the art video codec H.264/AVC. SE is performed in the context-based adaptive binary arithmetic coding (CABAC) module of video codec. For this purpose, CABAC is converted to an encryption cipher. It has been achieved through scrambling of equal length bin strings. In our scheme, CABAC engine serves the purpose of encryption cipher without affecting the coding efficiency of H.264/AVC by keeping exactly the same bit rate, generating completely compliant bitstream and utilizing negligible computational power. Owing to no escalation in bit rate, our encryption algorithm is better suited for real-time multimedia streaming. It is perfect for playback on handheld devices because of negligible increase in processing power. Nine different benchmark video sequences containing different combinations of motion, texture and objects are used for experimental evaluation of the proposed algorithm.