A method, an apparatus and a carrier medium for securely distributing
multimedia while still retaining compatibility with existing CA systems.
The method includes forming a packet including a plurality of encrypted
multimedia stream segments. The packet further includes, for each segment
of the plurality, a field providing conditional access information
associated with the segment. The method further includes sending the
packet to an intermediary. The method is such that the intermediary
receiving the packet can send a first segment of the plurality and any
associated conditional access information to a first receiver, and send a
second segment of the plurality and any associated conditional access
information to a second receiver. The method is also such that no
decryption of any segment of the plurality is required by the
intermediary to send the first segment or to send the second segment.