| 摘要 |
<p>In order to scramble in a most efficient way prepayment television programs, the emitter (1) sends both access messages and authorization messages, all crypted and corresponding to a control word periodically charged into a pseudo-random generator (6). In each receiver, the decoder is provided with a control unit (22) which processes the various messages and sends them to a security processor (23) which provides a control word to a pseudo-random generator (24) controlling the descrambling (14).</p> |
