Over the real-time selective encryption of AVS video coding standard

Audio Video Coding Standard (AVS) is the emerging video standard in which 2-dimensional context adaptive variable length coding (C2DVLC) is used. The main difference between context adaptive variable length coding (CAVLC) of H.264/AVC and C2DVLC of AVS from selective encryption point of view is that C2DVLC codewords are not contiguous and do not use the full code-space. In this case, C2DVLC codewords can be assigned indices and are encrypted. This scheme works fine if codewords are encrypted separately. But when we make a plaintext by encryptable bits of codewords, the encrypted codewords may not be valid codewords because C2DVLC encryptable bits do not use a full code-space. In this paper, we will present two schemes to overcome this limitation for real-time implementation of C2DVLC codewords. Both of the algorithms are a compromise between the processing power and security of realtime selective encryption.