| 摘要 |
<p>This invention discloses an apparatus and a method for receiving a plurality of encrypted digital video, audio and data that require an encryption key to decode before utilizing. Specifically the invention is directed toward devices such as cable and digital broadcast satellite systems that transmit multiple channel information to receivers that provide users access to the multiple channels upon particular channel selection. Such channel selection requires decrypting and formatting a new data stream through a time consuming electronic process. The invention described herein reduces channel change time, by monitoring de-scrambled data in the background, prior to a user selecting a new channel. Digital broadcast data contain input de-scrambling control words required for the decoding of N-bit de-scrambling keys for each of a multiplicity of digital data streams available. Storing the data control words or the N-bit descramble keys reduces subsequent retrieval decoding time. However, utilizing the control words to descramble the N-bit de-scrambling keys and then storing the N-bit de-scrambling keys, typically yields the greatest gain in reducing channel change time.</p> |
