1. A method for verifying an authenticity and integrity of an ordered sequence of digital video frames, the video frames including respective data, the digital 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; b) protecting the sequence by embedding a respective calculated digital signature in a least one video frame 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; and c) confirming an authenticity and integrity of said protected sequence, wherein said confirming comprises: i) extracting said embedded digital signature from each at least one frame of said protected sequence, thereby obtaining a frame signature; ii) calculating from each at least one frame of said protected sequence a new digital signature, using said secret key, thereby obtaining a stream signature; and iii) inferring authenticity and integrity by comparing said extracted digital signatures with respective said new calculated signatures for identity.