System for providing keys

Abstract

A method for providing keys for descrambling scrambled content, the scrambled content being divided into frames, the method including: identifying a plurality of frames to be descrambled; for each frame of the plurality of frames, identifying a key period associated with a key for descrambling the frame; and for at least one frame f of the plurality of frames, substituting a substitute frame g for the frame f, the substitute frame g being chosen in order to reduce a total number of key periods associated with keys for descrambling all of the plurality of frames. Related apparatus and methods are also provided.

1 - 21 . (canceled)  
     
     
         22 . A method for processing scrambled content, the scrambled content being divided into frames, the method comprising: 
 identifying a first plurality of frames to be descrambled, the first plurality of frames being associated with a second plurality of key periods;    choosing a first key period of the second plurality of key periods; and    identifying all frames of the first plurality of frames which are associated with the first key period and substituting, for each frame identified, a substitute frame not associated with the first key period to produce a new first plurality of frames, thereby reducing a total number of key periods associated with keys for descrambling all of the new first plurality of frames.    
     
     
         23 . The method according to  claim 22  and also comprising: 
 producing one key for each key period of the reduced total number of key periods.    
     
     
         24 . The method according to  claim 22  and also comprising: 
 producing exactly one key for each key period of the reduced total number of key periods.    
     
     
         25 . The method according to  claim 23  and wherein the producing comprises producing from an ECM.  
     
     
         26 . The method according to  claim 24  and wherein the producing comprises producing from an ECM.  
     
     
         27 . The method according to  claim 22  and also comprising: 
 rendering at least one of the new first plurality of frames.    
     
     
         28 . The method according to  claim 27  and wherein the rendering comprises rendering all of the new first plurality of frames.  
     
     
         29 . Apparatus for processing scrambled content, the scrambled content being divided into frames, the apparatus comprising: 
 a frame identifier identifying a first plurality of frames to be descrambled, the first plurality of frames being associated with a second plurality of key periods;    a key period identifier choosing a first key period of the second plurality of key periods; and    a frame substitutor identifying all frames of the first plurality of frames which are associated with the first key period and substituting, for each frame identified, a substitute frame not associated with the first key period to produce a new first plurality of frames, thereby reducing a total number of key periods associated with keys for descrambling all of the new first plurality of frames.    
     
     
         30 . Apparatus according to  claim 29  and also comprising: 
 key production apparatus for producing one key for each key period of the reduced total number of key periods.    
     
     
         31 . Apparatus according to  claim 30  and wherein the key production apparatus is operative to produce exactly one key for each key period of the reduced total number of key periods.  
     
     
         32 . Apparatus according to  claim 30  and wherein the producing comprises producing from an ECM.  
     
     
         33 . Apparatus according to  claim 31  and wherein the producing comprises producing from an ECM.  
     
     
         34 . Apparatus according to  claim 29  and also comprising: 
 rendering apparatus for rendering at least one of the new first plurality of frames.    
     
     
         35 . Apparatus according to  claim 34  and wherein the rendering comprises rendering all of the new first plurality of frames.