Selective encryption for trick play with improved security

摘要

Certain embodiments consistent with the present invention involve a method of selectively encrypting digital video content that involves receiving a plurality of packets containing the digital video content; identifying packets containing start of frame (SOF) headers; inserting padding into the packets containing SOF headers to move the content of the packets containing the SOF headers to a previous or subsequent packet and create padded packets containing the SOF headers; selecting certain of the packets for encryption according to a selection criterion, wherein the selected packets exclude the padded packets containing SOF headers; encrypting the selected packets; and retaining the padded packets containing the SOF headers unencrypted to form selectively encrypted digital video content. Corresponding decoding method as well as encoding and decoding apparatus are also taught. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.