System for permitting off-line playback of digital content, and for managing content rights

Abstract

A system for permitting offline content playback and for managing the rights to one or more digital content files within a computer network. The system manages these rights by encrypting the content files to prevent unauthorized access to the files. Encryption is accomplished by using one or more keys which are associated with one or more segments of the content file. These keys enable an authorized user to decrypt and playback the content files at a subsequent time. When the keys are received, a license which specifies the rights of the user regarding the content files, is obtained by the end user system, and verified locally to permit the content playback.

1 . A method for inhibiting unauthorized use of a digital content file, the method comprising: 
 removing a portion of said digital content file;    replacing said removed portion with a header,    said header including information enabling retrieval of said removed portion.    
   
   
       2 . A method according to  claim 1 , further comprising: 
 generating a license file; and    adding said removed portion to said license file,    said license file enabling recombination of the removed portion with said digital content file and allowing authorized use of said digital content file.    
   
   
       3 . A method according to  claim 2  wherein said license file includes machine specific information.  
   
   
       4 . A method according to  claim 1  wherein said digital content file is selected from the group consisting of: a musical recording, an audio file and a video file.  
   
   
       5 . A method for encrypting a digital content file, the method comprising: 
 encrypting at least one segment of said content file using at least one separate encryption key respectively.    
   
   
       6 . A method according to  claim 5 , further comprising: 
 storing said encryption keys in a database; and    retrieving said encryption keys from said database.    
   
   
       7 . A method according to  claim 6 , further comprising: 
 removing a portion of said digital content file; and    replacing said removed portion with a header,    said header including information enabling retrieval of said removed portion.    
   
   
       8 . A method according to  claim 7 , further comprising generating a license file for said content file, said license file comprising the removed portion of said content file for enabling recombination of the removed portion with said digital content file and allowing authorized use of said digital content file.  
   
   
       9 . A method according to  claim 8 , wherein said license file includes a user's machine specific information thereof.  
   
   
       10 . A method according to  claim 9  wherein said digital content file is selected from the group consisting of: a musical recording, an audio file and a video file.  
   
   
       11 . A method for permitting authorized use of a digital content file, the method comprising: 
 generating a modified digital content file, said generating including: 
 removing a portion of said digital content file; and  
 replacing said portion with a header, said header including information enabling an authorized user to retrieve said removed portion;  
   providing said modified digital content file to said authorized user; and    providing said authorized user access to said removed portion.    
   
   
       12 . A method according to  claim 11 , further comprising: 
 generating a license file, said license file including said removed portion; and    providing said license file to said authorized user.    
   
   
       13 . A method according to  claim 12  wherein said license file further comprises a machine identifier.