A selective encryption encoder and method of dual selective encryption and
detection of intra-coded slices in video content. The selective
encryption encoder has a packet identifier that identifies packets of at
least one specified packet type, the at least one specified packet type
being packets in a set of N consecutive slices in a frame wherein the a
second byte after a slice start code is identical in all N consecutive
slices. 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.