SYSTEM FOR PROVIDING SCRAMBLED CONTENT, AND SYSTEM FOR DESCRAMBLING SCRAMBLED CONTENT

摘要

A system for providing scrambled content, comprising a control word generator,each control word including a control word identifier, a scrambler forproviding a stream of scrambled data packets, and an encryption device forproviding entitlement control messages (ECM's). One or more consecutivepackets are scrambled using the same control word (CW). Each packet includes acontrol word identifier. An ECM decryption device delivers control words tothe descrambler and the descrambler descrambles the data packets of thescrambled content using a control word having a control word identifiercorresponding with the control word identifier of the data packet to bedescrambled. The system further comprises a storage device for storingscrambled content and means to control play back of the stored content, goingfast forward and going backwards.