| 摘要 |
<p>A method and apparatus for enabling session-based conditional access to on-demand content of variable duration by scrambling (314) a program stream provided to a set top terminal via a defined communications channel; communicating (316) to the set top terminal while establishing a session, via one of the defined communications channel and an out-of-band communications channel, an authorization message and descrambling message suitable for determining a descrambling key for descrambling the program stream; and including (330), within the program stream being scrambled, content requested by the set top terminal.</p> |
