With the increase of Internet bandwidth

applications based on video stream have been developed rapidly. But the applications

such as digital video

videomail or videophone

are very vulnerable in network environment. Therefore video security has become an important research field. In recent years

a lot of image and video encryption algorithms and techniques have been used to solve the problem. However

most of them have drawbacks in security or speed. Combining with other algorithms’virtues

this article puts forward amethod that uses both stream ciphers to generate pseudo random numbers and block ciphers to do permutation. A 4 dimensional hyperchaotic function is chosen as stream ciphers

and Baker map as block ciphers. The improved Bakermap canwithstand known plain text attack in simple form. And the 4 dimensional hyperchaotic function can not only enhance encryption speed but also increase cipher complexity. This method

which can be simply realized by software

is independent of any kind of video compression algorithms

while providing high security for real time digital video with fast encryption speed.