Multiple partial encryption

摘要

A method of encrypting a digital television signal carried out in any operative order involves duplicating packets in the digital television signal so as to create first and second duplicate packets; encrypting the first duplicate packets according to a first encryption method to create first encrypted packets; encrypting the second duplicate packets according to a second encryption method to create second encrypted packets; identifying packets in the digital television signal that are of a packet type, while other packets are not of the packet type; replacing the identified packets in the digital television signal with corresponding first and second encrypted packets to produce a multiple partially encrypted digital television signal comprising the other packets that are unencrypted and the first and second encrypted packets; and distributing the multiple partially encrypted digital television signal. This abstract is not to be considered limiting as other embodiments may include more or fewer or differing elements than appear in the abstract.