Patent ID: 6587561
Filing Date: 2003-07-01
Classification: H04N

Abstract:
A key delivery method for use in an encoded communications system in which a first plurality of encoded items comprising at least a first item encoded with a first item control word and a second item encoded with a second item control word is sent in a communication stream from a sender to a receiver, the method comprising:transmitting a first item entitlement control message (IECM) comprising first item control information for controlling only the first item and a second IECM comprising second item control information for controlling only the second item; transmitting a stream entitlement control message (SECM) comprising stream control information for controlling more than one item; combining at least part of the first item control information and at least part of the stream control information to produce the first item control word; and combining at least part of the second item control information and at least part of the stream control information to produce the second item control word, wherein said transmitting-IECM step is performed before said transmitting-SECM step.