Aiming at secure video sharing in multimedia social network, a format-compliant encryption scheme for high efficiency video coding (HEVC) based on sigh data hiding (SDH) is proposed. The encryption is tightly integrated with the encoding/decoding processes. For each coding unit (CU), the sign of the nonzero coefficient and the first hiding nonzero coefficient are both encrypted with key stream. Meanwhile, one of merging index, motion vector prediction index, sign of motion vector difference and reference frame index is chosen for encryption according to a control factor. As it is explored in this article, experimental results and analysis indicate that it can effectively resist brute-force attack, difference attack and replacement attack. Also, it can keep a good balance in encryption space, computation complexity and security. Based on the encryption scheme, a framework of its implementation in multimedia social network is presented. It has great potential to be implemented for secure video sharing in multimedia social network.

Aiming to protect H. 264/AVC video in multimedia social network, a selective encryption scheme is put forward. In the scheme, after analyzing the impact of quantization parameter (QP) on the encryption of the sign of T1 s and the impact of encrypting intermacroblock non-zero coefficients, the sign of intra-macroblock non-zero DCT coefficients, the sign of trailing ones (T1 s), the intra prediction modes (IPMs) and the sign of motion vector difference (MVD) are encrypted to protect the texture and motion information of H. 264/AVC. Experimental results and analysis show that the computation cost is low and the bitrate increment is negligible, and it can achieve good performance in resisting brute-force attacks, histogram-based attacks and replacement attacks. Based on the encryption scheme, a framework of its implementation in multimedia social network is put forward. It has great potential to be implemented for the video data protection in multimedia social network.