Patent ID: 7746853

Claim:
A method of operating a packet communication device, the method comprising: forming a packet including a plurality of multimedia transport packets in which a plurality of multimedia stream segments may be encrypted, the packet substantially conforming to a Secure Real Time Protocol (“Secure RTP”, “SRTP”) packet structure as specified in RFC-3550 and RFC-3711 such that the packet can be interpreted as an SRTP packet by an SRTP compatible device, the packet including an RTP header that is unencrypted, and an RTP payload portion, the RTP payload portion including the multimedia transport packets, each multimedia transport packets including a media transport packet header and a media payload portion; and sending the packet to an intermediary, wherein in the case the media payload portion of a media transport packet is encrypted, the media transport packet header is unencrypted, such that at least some of the RTP payload portion is not encrypted, wherein the packet can include two different media transport packets with respective media payload portions that are encrypted differently, and wherein the packet includes an additional field that is not part of the SRTP standard specified in RFC-3550 and RFC-3711, the additional field providing conditional access information associated with each encrypted multimedia stream segment included in the packet, and such that the intermediary receiving the packet can send the multimedia transport packet or packets for a first segment of the plurality and any associated conditional access information to a first receiver, and send the multimedia transport packet or packets for a second segment of the plurality and any associated conditional access information to a second receiver without needing to decrypt any encrypted media payload portions of the first or second segments in the case the first stream segment or the second stream segment is encrypted.