STORAGE OF ENCRYPTED DIGITAL SIGNALS

摘要

Digital video signals are encrypted by a broadcaster based on a key stream and transmitted to a receiver. At the receiver, the signals are decrypted (13) using the broadcaster's keys and processed (17) in unencrypted form to improve recording and/or playback operation. The processed signals are then re-encrypted (18) using the broadcaster's keys, with appropriate time-shifting (20) to align key changes with suitable boundaries in the video stream. The resulting encrypted signals are stored on a storage medium (19).