A selective encryption encoder consistent with certain embodiments of the
invention has a packet identifier that identifies packets of a specified
packet type, the specified packet type being defined by packets occurring
in a star pattern approximately situated at an upper center of an image
which contain intra-coded macroblocks. A packet duplicator duplicates the
identified packets to produce first and second sets of the identified
packets. The packets are sent to and from a primary encryption encoder to
encrypt the first set of identified packets under a first encryption
method. A secondary encrypter encrypts the second set of identified
packets under a second encryption method.