A Novel Stream Cipher for Video Compressed by H.264

The characteristics of video data are very large amount and real time processing request, and H.264 is a high-complexity video compression standard, so a high speed arithmetic is needed for encrypting video data which is encoded by H.264 standard. But, for a high security video application, it´s difficult to find an algorithm to meet the two requests: high security, high speed. A new stream cipher is introduced at this article which uses a parameter to balance the security and computing speed, and then the requests for security and computing speed will be fit, by encrypting important data with high-security parameter and encrypting unimportant data with high-speed parameter.