Sparse Selective Encryption for HEVC 4K Video Using Spatial Error Spread

This paper proposes a universal HEVC SE method named Sparse Selective Encryption (SSE), which encrypts a few of bits on the bitstream without coupling with the encoder. High efficiency of the SSE results from using spatial correlation of prediction units to propagate the error from encrypted units. The sparse selection of key units is decided by two spatial influence models, which are designed according to the angular intra prediction mode and the motion vector prediction direction respectively. SSE allows user to customize the encryption density of the bitstream by adjusting the proportion of selected coding units. Additionally, the format compliance of the bitstream is kept by performing bit encryption on the bits of cipherable syntax elements of selected units using the modified AES CTR cipher. The paper presents the comprehensive security analysis and efficiency performance of the SSE, including visual perception, cryptography attack and computation cost. Achieved experiment results confirm that SSE is secure and effective to protect HEVC 4K videos and backwards compatible with lower resolution videos.