Abstract :
When the early conditional access concepts were first being discussed, there were many different ideas on how the conditional access function should be realised. Should the security device be completely buried in the receiver and controlled entirely by over-air addressing, or should over-air addressing not exist at all and smart cards used to provide the complete conditional access function. Most people would now agree that over-air addressing is essential, particularly at the start of the service, in order to underpin any pay television business. Although smart cards give added flexibility by virtue of their replaceability, it seems that they will not come along until later, and will still need to be over-air addressed. The current thinking amongst most people working in the subject is that the first set-top adaptor for MAC will contain a buried security device with an external interface
