A selective encryption encoder consistent with certain embodiments of the
invention has vertical and/or horizontal stripes encrypted. In one
embodiment, packets are examined in the digital video signal to identify
a specified packet type, the specified packet type being both packets
carrying intra-coded data representing a pattern of horizontal stripes
across an image and packets carrying intra-coded data representing a
pattern of vertical stripes across an image. The packets identified as
being of the specified packet type are encrypted using a first encryption
method to produce first encrypted packets. These first encrypted packets
are then used to replace the unencrypted packets in the digital video
signal to produce a partially encrypted video signal. The packets of the
specified type can also be multiple encrypted and replaced in the data
stream to produce a multiple encrypted video data stream. This abstract
is not to be considered limiting since embodiments consistent with the
present invention may incorporate more, fewer or differing elements than
mentioned in this abstract.