Format-compliant encryption techniques for high efficiency video coding

When middlebox devices should be able to adapt an encrypted video stream in the network without having the decryption key, format-compliant partial encryption schemes should be applied. In this paper, we propose such encryption schemes for the recently standardized High Efficiency Video Coding (HEVC) standard. By encrypting specific syntax elements like the sign of the residual information, the sign of the motion vector (MV) difference, the MV prediction index, and the MV reference index, format compliance and the possibility for adaptation are offered. Scrambling performance gradually increases when shifting from encrypting the motion information to encrypting the residual sign and finally to the combination thereof. Applying all these techniques has a negligible impact on the compression efficiency