scope:

This document describes the VideoGuard access control system for MAC/Packet family of transmissions, which includes D2MAC. This access control system operates in the context of the MAC/Packet system defined in Reference 1. The access control system ensures that programs (or data services) are available only to viewers who have met certain conditions (usually payment). The VideoGuard access control system (ACS) proposed in this document consists of a smart card and a software module embedded in the decoder (VideoGuard's ACS module is known as the "verifier"). Certain support functions are implemented in the decoder. The VideoGuard system as described herein is backward compatible with existing PAL installations, permitting a broadcaster to issue one set of cards to all viewers, whether they are receiving MAC or PAL transmissions. It is the opinion of VideoGuard's designers that this flexibility is critical for the financial success of the proposed D2MAC access control system. Additional functions have been specified for an enhanced VideoGuard installation.