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: stream; (b) decrypting and transmitting the bit stream to which the header area is added: 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 step (c) and optionally recording it an on a 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 digital video content included in said received digital data stream based on said decrypted encryption key; and  
 (e) transmitting said decrypted digital data stream video content to at least one of a monitor and a digital recorder reproducing device and a recording device.  
 
     
     
       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 operates on units of a predetermined block of said received digital data stream . 
     
     
       4. A copy prevention apparatus for a digital video system comprising:
 receiving means for receiving aa receiver to receive 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 digital video content included in said received digital data stream based on said decrypted encryption key; and  
 a controller to control transmission of said decrypted digital data stream video content to at least one of a monitor and a digital recorder reproducing device and a recording device.  
 
     
     
       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 operates on units of a predetermined block of said received digital data stream . 
     
     
       7. A copy prevention method for a digital video data 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; and  
 (d) decrypting digital content included in said received digital data stream based on said decrypted encryption key.  
 
     
     
       8. A copy prevention method for a digital video data system as claimed in  claim 7 , wherein said key information is predetermined by said digital video data system. 
     
     
       9. A copy prevention method for a digital video data system as claimed in  claim 7 , wherein said decrypting step (d) is operated in operates on units of a predetermined block of said received digital data stream. 
     
     
       10. A copy prevention apparatus for a digital video data system comprising:
 receiving means for receiving aa receiver to receive 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; and  
 a decryption unit to decrypt said encryption key using key information and to decrypt digital content included in said received digital data stream based on said decrypted encryption key.  
 
     
     
       11. A copy prevention apparatus for a digital video data system as claimed in  claim 10 , wherein said key information is predetermined by said digital video data system. 
     
     
       12. A copy prevention apparatus for a digital video data system as claimed in  claim 10 , wherein said decryption unit is operated in operates on units of a 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 digital video content included in 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 operates on units of a predetermined block of said received digital data stream . 
     
     
       15. A copy prevention apparatus for a digital video system comprising:
 a receiving means for receiving aunit to receive 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 digital video content included in 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 operates on units of a 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 step (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 a copy prevention function in a digital data processing device, comprising:
 a digital data area for storing digital data encrypted using first key information; and  
 a key information area for 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 involves a 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 uses a public key encrypts to encrypt 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. The recording medium of  claim 23 , wherein the first key information is randomly selected.