Copy prevention method and apparatus for digital video system

Abstract

A copy prevention method and apparatus for a digital video system is disclosed including the steps of: (a) adding a header area of a header start code and key field to a reproduced bit stream: (b) decrypting and transmitting the bit stream to which the header area is added: (c) detecting a key field of the decrypted and transmitted bit stream and detecting copy prevention information; and (d) encrypting the bit stream according to information detected from stop (c) and recording it an tape.

1. A copy prevention method for a digital video system comprising the steps of:
 (a) receiving a digital data stream reproduced from a digital medium;   (b) detecting an encryption key, which is a portion of said received digital data stream;   (c) decrypting said encryption key using key information;   (d) decrypting said received digital data stream based on said decrypted encryption key; and   (e) transmitting said decrypted digital data stream to at least one of a monitor and a digital recorder.   
     
     
       2. A copy prevention method for a digital video system as claimed in  claim 1 , wherein said key information is predetermined by said digital video system. 
     
     
       3. A copy prevention method for a digital video system as claimed in  claim 1 , wherein said decrypting step (d) is operated in units of predetermined block of said received digital data stream. 
     
     
       4. A copy prevention apparatus for a digital video system comprising:
 receiving means for receiving a digital data stream reproduced from a digital medium;   a key detector to detect an encryption key, which is a portion of said received digital data stream;   a decryption unit to decrypt said encryption key using key information and to decrypt said received digital data stream based on said decrypted encryption key; and   a controller to control transmission of said decrypted digital data stream to at least one of a monitor and a digital recorder.   
     
     
       5. A copy prevention apparatus for a digital video system as claimed in  claim 4 , wherein said key information is predetermined by said digital video system. 
     
     
       6. A copy prevention apparatus for a digital video system as claimed in  claim 4 , wherein said decryption unit is operated in units of predetermined block of said received digital data stream. 
     
     
       7. A copy prevention method for a digital video system comprising the steps of:
 (a) receiving a digital data stream reproduced from a digital medium;   (b) detecting an encryption key, which is a portion of said received digital data stream;   (c) decrypting said encryption key using key information;   (d) decrypting said received digital data stream based on said decrypted encryption key.   
     
     
       8. A copy prevention method for a digital video system as claimed in  claim 7 , wherein said key information is predetermined by said digital video system. 
     
     
       9. A copy prevention method for a digital video system as claimed in  claim 7 , wherein said decrypting step (d) is operated in units of predetermined block of said received digital data stream. 
     
     
       10. A copy prevention apparatus for a digital video system comprising:
 receiving means for receiving a digital data stream reproduced from a digital medium;   a key detector to detect an encryption key, which is a portion of said received digital data stream;   a decryption unit to decrypt said encryption key using key information and to decrypt said received digital data stream based on said decrypted encryption key.   
     
     
       11. A copy prevention apparatus for a digital video system as claimed in  claim 10 , wherein said key information is predetermined by said digital video system. 
     
     
       12. A copy prevention apparatus for a digital video system as claimed in  claim 10 , wherein said decryption unit is operated in units of predetermined block of said received digital data stream. 
     
     
       13. A copy prevention method for a digital video system comprising the steps of:
 (a) receiving a digital data stream reproduced from a digital medium;   (b) detecting an encryption key, which is a portion of said received digital data stream;   (c) decrypting said encryption key using predetermined key information;   (d) decrypting said received digital data stream based on said decrypted encryption key.   
     
     
       14. A copy prevention method for a digital video system as claimed in  claim 13 , wherein said decrypting step (d) is operated in units of predetermined block of said received digital data stream. 
     
     
       15. A copy prevention apparatus for a digital video system comprising:
 receiving means for receiving a digital data stream reproduced from a digital medium;   a key detector to detect an encryption key, which is a portion of said received digital data stream;   a decryption unit to decrypt said encryption key using predetermined key information and to decrypt said received digital data stream based on said decrypted encryption key.   
     
     
       16. A copy prevention apparatus for a digital video system as claimed in  claim 15 , wherein said decrypting unit is operated in units of predetermined block of said received digital data stream. 
     
     
       17. A copy prevention method for a digital data system, comprising the steps of:
 (a) receiving first key information;   (b) encrypting second key information using said first key information;   (c) encrypting digital data streams using said second key information; and   (d) recording at least said encrypted second key information and said encrypted digital data streams on a digital medium.   
     
     
       18. The method of  claim 17 , wherein said (b) randomly selects said second key information. 
     
     
       19. The method of  claim 17 , wherein said step (c) encrypts said digital data streams in blocks. 
     
     
       20. A copy prevention apparatus for a digital data system, comprising the steps of:
 an encryption unit receiving first key information, encrypting second key information using said first key information, and encrypting digital data streams using said second key information; and   a controller controlling recording of at least said encrypted second key information and said encrypted digital data streams on a digital medium.   
     
     
       21. The apparatus of  claim 20 , wherein said encryption unit randomly selects said second key information. 
     
     
       22. The apparatus of  claim 20 , wherein said encryption unit encrypts said digital data streams in blocks. 
     
     
       23. A recording medium having a data structure for controlling operation of copy prevention function in a digital data processing device, comprising:
 a digital data area storing digital data encrypted using first key information; and   a key information area storing said first key information encrypted using second key information, said first key information operatively controlling the decryption of said encrypted digital data in a digital data process device.   
     
     
       24. A copy prevention method for a digital data system, comprising:
 receiving first key information, said first key information for encrypting digital data;   encrypting said first key information using second information; and   transferring said encrypted first key information.   
     
     
       25. The method of  claim 24 , wherein said encrypting step public key encrypts said second key information. 
     
     
       26. The method of  claim 24 , wherein said transferring step records said encrypted first key information on a digital medium. 
     
     
       27. The method of  claim 24 , wherein said transferring step transmits said encrypted first key information. 
     
     
       28. A copy prevention apparatus for a digital data system, comprising:
 an encryption unit receiving first key information, said first key information for encrypting digital data, and encrypting said first key information using second key information; and   a controller controlling a transfer of said encrypted first key information.   
     
     
       29. The apparatus of  claim 28 , wherein said encryption unit public key encrypts said first key information. 
     
     
       30. The apparatus of  claim 28 , wherein said controller controls recording said encrypted first key information on a digital medium. 
     
     
       31. The apparatus of  claim 28 , wherein said controller controls transmitting said encrypted first key information. 
     
     
       32. A copy protection method for a digital data system, the method comprising:
 detecting, via a decryption device included in the digital data system, key information and copy prevention information from received digital data or from a signal reproduced from a digital recording medium, the key information for decrypting digital content from the received digital data or from the signal, the copy prevention information for indicating at least whether or not a copy of the digital content is permitted; and   controlling, via a controller within the digital data system, a copy protection function for the digital content based on the copy prevention information and the key information,   wherein said controlling step controls the copy protection function such that the digital content is not copied, when the copy prevention information indicates that a copy is not permitted, and   wherein said copy protection function includes identifying whether the digital content is encrypted based on classification information detected from the digital data, and decrypting, via the decryption device according to control of the controller, the digital content based on the key information if the digital content is encrypted.   
     
     
       33. The method of claim 32, wherein said controlling step (b) controls the copy protection function such that the digital content is decrypted only when the key information is detected. 
     
     
       34. The method of claim 32, wherein the copy prevention information includes information indicating a first recording source can copy the digital content onto a first recording medium but a second recording source can then not copy the digital content from the first recording medium to a second different recording medium. 
     
     
       35. An apparatus for copy prevention, comprising:
 a receiving device configured to receive a digital data stream;   a detecting device configured to detect an encryption key from the received digital data stream, and to detect copy prevention information from the received digital data stream, the encryption key for decrypting digital content from the received digital data stream and the copy prevention information for indicating whether or not a copy of the digital content of the digital data stream is permitted; and   a controller configured to control a copy protection function for the digital content based on the detected copy prevention information and key information,   wherein said controller is configured to control the copy protection function such that the digital content is not copied, when the copy prevention information indicates that a copy is not permitted, and   wherein said controller is configured to identify whether the digital content is encrypted based on classification information detected from the digital data stream, and control to decrypt the digital content based on the key information if the digital data stream is encrypted.   
     
     
       36. The apparatus of claim 35, further comprising:
 a decryption device configured to decrypt the digital content based on the encryption key, according to the control of the controller.   
     
     
       37. The apparatus of claim 36, wherein said decryption device is configured to operate on units of predetermined blocks of the digital content, according to the control of the controller. 
     
     
       38. The apparatus of claim 35, wherein the encryption key is predetermined by the digital content. 
     
     
       39. The apparatus of claim 35, wherein the copy prevention information includes information indicating a first recording source can copy the digital content onto a first recording medium but a second recording source can then not copy the digital content from the first recording medium to a second different recording medium.