【摘要】 为了将H.265编码框架与加密算法更好地结合起来,实现实时应用,提出了一种高效选择性加密算法,它使用RC6算法加密H.265视频比特流中对视频质量影响较高的数据,具有码流兼容性,且计算量低,加密速度快,可以用于实时应用.算法选择了6种语法元素进行加密,分别是量化变换参数的符号位和幅值绝对值残差后缀,运动矢量差(motion vector difference, MVD)的符号位和幅值绝对值残差后缀,以及离散余弦变换(discrete cosine transform, DCT)变换系数的符号位和幅值绝对值的残差后缀.实验使用4个分辨率与帧率不同的测试序列,加密后视频能够被标准解码器正常播放,PSNR值在10左右,SSIM值在0.3左右,RGB直方图存在明显差异,且每一帧的加密时间仅占原始编码时间的2%～3%,这说明本算法在保证了码流兼容性与安全性的前提下,实现了快速加密处理.更多还原

【Abstract】 In order to integrate H.265 coding framework with encryption algorithm better and realize real-time application, an efficient partial encryption algorithm is proposed. It uses RC6 algorithm to encrypt syntaxes which has high impact on video quality in H.265 video bit stream. It has bit stream compatibility, low computational complexity and fast encryption speed, and can be used in real-time application. Six kinds of grammar elements are chosen to encrypt the algorithm. They are the sign bits of quantized transformation coefficients and the absolute residual suffixes of value, the sign bits of motion vector difference(MVD) and the absolute residual suffixes of value, and the sign bits of discrete cosine transform(DCT) coefficients and the absolute residual suffixes of value. Four test sequences with different resolution and different frame rate are used in the experiment. The encrypted video can be played normally by standard decoder. The PSNR value is about 10, the SSIM value is about 0.3, and the RGB histogram is obviously different. The encrypted time of each frame is only 2%～3% of the original encoding time. This shows that the algorithm guarantees the compatibility of the stream. With the premise of security, fast encryption is achieved.更多还原