提出一种基于脆弱水印的视频流完整性认证方法，在H.264压缩比特流中，首先根据I_Slice 中4×4块的编码模式生成认证码，然后通过调制某些运动子块的VLC码字将其嵌入B_Slice和P_Slice的视频流中。这种调制是基于VLC码字和待嵌入比特之间的映射规则进行的。映射后的码字与原码字具有很好的相似性，即码字长度不变，码字表示的编码元素值相似。该算法可以实现水印的快速提取，满足视频实时处理的要求。实验仿真结果表明，本算法具有较小的视频失真，并能有效地对视频帧进行完整性认证。

An integrity authentication scheme for video bit-stream based on the fragile watermarking is proposed in this paper. In the compressed bit-stream of H.264, The authentication codeword are generated according to the mode of intra_4×4 in I_Slice firstly, and then embedded into B_Slice and P_Slice by modulating some VLC codeword of sub-block. This modulation is based on the mapping rule between the VLC codeword and the bit to be embedded. The mapped codeword is very similar to the original codeword, namely, the length of codeword is same and the value of coding element is similar. This scheme could detect the watermarking rapidly, which meets the requirement of the real-time processing of video. Experimental results show that it has less influence on the quality of video, and can effectively carry out the integral certification of video frame.