Method and apparatus for scrambling and/or descrambling digital video data and digital audio data using control data

Abstract

A copy prevention method and apparatus of a digital magnetic recording/reproducing system performs the copy prevention function by encoding to insert a marker involving copy prevention function information and executing the function and allows a program supplier to realize a desired copy prevention function of various patterns, in which the marker formed by a control word for scrambling audio and video bit straps and copy prevention information for preventing an illegal copy is encrypted by an encoded key to be multiplexed with the audio and video bit strips scrambled by the control word. The marker transmitted is detected from the bit strips to be decrypted and analyzed by the encoded key to determine whether the copy is permitted or not, so that the detected marker is updated to be recorded on a video tape and the control word is produced from the marker to perform the descrambling to supply the result to a monitor to be displayed. Thus, the program supplier selects the copy prevention function, and a separate format converting apparatus is not required since a field defined within a GA format is utilized while an existing DVCR is not need to be changed for performing the copy prevention function as the data amount to be recorded is not increased.A method and apparatus for descrambling data are discussed. According to an embodiment, the invention provides a method of descrambling digital data using a digital data processing apparatus, the digital data processing apparatus including a descrambler, the method comprising: Initializing, by the digital data processing apparatus, the descrambler of the digital data processing apparatus based on control data to descramble a received digital data stream, the digital data stream being comprised of a plurality of packet units each including payload data, a first packet unit among the packet units further including a heading portion including the control data, wherein the descrambler is initialized based on the control data in the first packet unit for descrambling the first packet unit and one or more succeeding packet units; and descrambling, by the descrambler, the payload data in each of the packet units.