Partial encryption and PID mapping

摘要

A method of encoding a packetized digital television signal consistent with certain embodiments involves encrypting a portion of the packets containing the digital television signal according to a first encryption algorithm; encrypting the portion of the packets containing the digital television signal according to a second encryption algorithm; leaving a portion of the packets containing the digital television signal unencrypted; assigning a primary packet identifier to the unencrypted packets; assigning a primary packet identifier to the packets encrypted under the first encryption algorithm; and assigning a secondary packet identifier to the packets encrypted under the second encryption algorithm. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.