CONDITIONAL ACCESS SYSTEM AND APPARATUS

摘要

A signal (24) that contains a stream of encrypted data and a plurality of individually identified streams (20, 22) of messages. Each of the streams (20, 22) of messages contains decryption information for decrypting a common part of the encrypted data. In a receiving and recording apparatus a mode selection unit (16) selects an operating mode from a plurality of modes including a live rendering mode and a replay mode for rendering the signal with a rendering unit (14) when received live and when replayed from storage respectively. A decoder (14) decrypts the encrypted data using a selectable one of the streams of messages. The decoder (14) selects the stream of messages dependent on the selected operating mode.