1. A television set-top box, comprising: a receiver receiving a digital television signal comprising: a plurality of unencrypted packets; and a plurality of multiple selectively encrypted sets of packets, wherein the encrypted packets are of at least one selected packet type and the at least one selected packet type comprises at least one of the following: packets containing a video slice header appearing in an active region of a video frame, any packet carrying data describing an active region of a video frame, I Frame packets, packets containing motion vectors in a first P frame following an I Frame, packets having an intra_slice_flag indicator set, packets having an intra_slice indicator set, packets containing an intra_coded macroblock, packets that carry data for a slice containing an intra_coded macroblock, packets containing data from a first macroblock following the video slice header, packets containing video slice headers, packets containing anchor data, and P Frame packets for progressively refreshed video data; a decrypter that decrypts one of the sets of multiple selectively encrypted packets; and a decoder that decodes the unencrypted packets and the decrypted packets to produce a signal suitable for play on a television set.