| 摘要 |
A method of transmitting control words to terminals that are mechanically and electronically independent of one another includes transmitting, to a terminal, an absent control word in response to a request from the terminal that contains a cryptogram corresponding to the absent control word, for the terminal, selectively determining a number of additional control words to be transmitted to the terminal as a function of a probability that security of the additional control words is compromised, and transmitting, to the terminal, in addition to the absent control word, the determined number of additional control words to enable the terminal to descramble at least one additional cryptoperiod of the multimedia content in addition to the cryptoperiod of the multimedia content that can be descrambled using the absent control word. |
