Patent ID: 7287168

Claim:
A method of encoding a packetized digital television signal, comprising: encrypting a portion of 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; so that the portion of the packets containing the digital television signal are encrypted according to a first encryption algorithm and a copy of the portion of the packets containing the digital television signal are encrypted according to the 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; assigning a second packet identifier to the packets encrypted under the second encryption algorithm; assembling the packets having the primary packet identifier and containing the unencrypted digital television signal, the packets having the primary packet identifier encrypted under the first encryption algorithm, and the packets having the secondary packet identifier encrypted under the second encryption algorithm into a stream of packets; and sending the assembled stream of packets to a transmitter for transmission to a plurality of recipients.