1. A method for verifying an authenticity and integrity of an ordered sequence of digital video frames, the video frames including respective data, the video frames including Inter frames and Intra frames both including segments, the segments of the Inter frames including Inter segments and Intra segments, the segments of the Intra frames including Intra segments, the method comprising the steps of: a) providing at least one secret key; and b) protecting the sequence by embedding a respective calculated digital signature in each of said video frames to produce a protected sequence: i) each said calculated digital signature being dependent on the data of another video frame; ii) each said calculated digital signature being generated using one of said at least one secret key; and iii) each said calculated digital signature being embedded according to an embedded pattern.