STAR PATTERN PARTIAL ENCRYPTION

摘要

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.