System and method for processing conditional access data

Abstract

A computer-implemented method is disclosed comprising: storing a first encrypted multimedia stream on a storage device as the stream is broadcast by a content provider; storing a stream of conditional access data on the storage device, the stream of conditional access data associated with the multimedia stream; and decrypting the first encrypted multimedia stream from a specified point within the encrypted multimedia stream using the stream of conditional access data, responsive to a user request to play back the encrypted multimedia stream from the specified point.

What is claimed is:  
     
         1 . A computer-implemented method comprising: 
 storing a first encrypted multimedia stream on a storage device as said stream is broadcast by a content provider;    storing a stream of conditional access data on said storage device, said stream of conditional access data associated with said multimedia stream; and    decrypting said first encrypted multimedia stream from a specified point within said encrypted multimedia stream using said stream of conditional access data, responsive to a user request to play back said encrypted multimedia stream from said specified point.    
     
     
         2 . The computer-implemented method as in  claim 1  wherein decrypting further comprising: 
 reading conditional access data from said stream of conditional access data from said specified point concurrently with reading said first encrypted multimedia stream from said specified point, said conditional access data identifying successive keys for decrypting corresponding successive portions of said first encrypted multimedia stream.  
 
     
     
         3 . The method as in  claim 2  further comprising: 
 providing said successive keys identified by said conditional access data to a conditional access module wherein said conditional access module uses said successive keys to decrypt corresponding successive portions of said first encrypted multimedia stream to produce a first decrypted multimedia stream.  
 
     
     
         4 . The method as in  claim 3  further comprising: 
 decoding said first decrypted multimedia stream using a specified codec.  
 
     
     
         5 . The method as in  claim 4  wherein said specified codec is MPEG-2.  
     
     
         6 . The method as in  claim 2  wherein a secure micro unit provides said successive keys to said conditional access module responsive to reading said conditional access data.  
     
     
         7 . The method as in  claim 1  further comprising: 
 storing a second encrypted multimedia stream on said storage device at the same time as said first encrypted multimedia stream is stored to said storage device, wherein said stream of conditional access data contains conditional access data associated with said second encrypted multimedia stream as well as said first multimedia stream;  
 decrypting said second encrypted multimedia stream using said stream of conditional access data responsive to a user request to play back said second encrypted multimedia stream from a specified point within said second encrypted multimedia stream.  
 
     
     
         8 . The method as in  claim 7  wherein said first and second multimedia streams are stored on said storage device in a multiplexed format.  
     
     
         9 . The method as in  claim 8  wherein said multiplexed format comprises a series of packets containing multimedia data for said first and second multimedia streams.  
     
     
         10 . The method as in  claim 1  further comprising: 
 performing a lookup in a timestamp index using a specified point in time to identify said specified point within said first encrypted multimedia stream to begin decrypting.  
 
     
     
         11 . The method as in  claim 10  wherein said timestamp index is comprised of a set of timestamps and corresponding address pointers, said address pointers identifying said specified point within said first encrypted multimedia stream from which to begin decryption.  
     
     
         12 . The method as in  claim 10  wherein said timestamp index is transmitted by said content provider.  
     
     
         13 . The method as in  claim 11  wherein said address pointers point to I-frames within said multimedia stream.  
     
     
         14 . The method as in  claim 10  further comprising: 
 generating said timestamp index in real time as said first encrypted multimedia stream is received.  
 
     
     
         15 . The method as in  claim 14  further comprising: 
 identifying an I-frame within said first encrypted multimedia stream by decrypting said first encrypted multimedia stream from said specified point in time until an I-frame is reached.  
 
     
     
         16 . The method as in  claim 15  further comprising: 
 decrypting and decoding said I-frame as well as any B and P frames following said I-frame; and  
 rendering said multimedia stream on a display beginning with said I-frame.  
 
     
     
         17 . An apparatus for processing multimedia streams and conditional access data comprising: 
 a mass storage device to store a first encrypted multimedia stream and associated conditional access data; and    selection logic to identify a first subset of said conditional access data to be used to decrypt said first encrypted multimedia stream from a specified point within said first encrypted multimedia stream.    
     
     
         18 . The apparatus as in  claim 17  further comprising: 
 a conditional access module to decrypt said first encrypted multimedia stream using said first subset of conditional access data.  
 
     
     
         19 . The apparatus as in  claim 17  further comprising: 
 a secure micro unit to read said first subset of conditional access data and identify a series of decryption keys responsive thereto; and  
 a conditional access module to use said series of decryption keys to decrypt said first encrypted multimedia stream from said specified point within said encrypted multimedia stream.  
 
     
     
         20 . The apparatus as in  claim 17  wherein said mass storage device stores a second encrypted multimedia stream and wherein said selection logic identifies a second subset of said conditional access data to be used to decrypt said second encrypted multimedia stream from a specified point within said second encrypted multimedia stream.  
     
     
         21 . The apparatus as in  claim 20  further comprising: 
 a conditional access module to decrypt said first and second encrypted multimedia streams using said first and second subsets of conditional access data, respectively.  
 
     
     
         22 . The apparatus as in  claim 21  further comprising: 
 a secure micro unit to read said first and second subsets of conditional access data and identify a first and second series of decryption keys responsive thereto; and  
 a conditional access module to use said first and second series of decryption keys to decrypt said first and second encrypted multimedia streams from said specified points within said first and second encrypted multimedia stream.  
 
     
     
         23 . The apparatus as in  claim 20  further comprising 
 a multi-stream PID filter module to demultiplex said first multimedia stream from said second multimedia stream prior to rendering said first multimedia stream on said display.  
 
     
     
         24 . The apparatus as in  claim 23  wherein said multi-stream PID filter demultiplexes said first multimedia stream from said second multimedia stream prior to storing said first and second multimedia streams on said storage device.  
     
     
         25 . The apparatus as in  claim 17  further comprising: 
 a timestamp index used by said selection logic to identify said first specified point within said first encrypted multimedia stream to begin decrypting.  
 
     
     
         26 . The apparatus as in  claim 25  wherein said timestamp index is comprised of a set of timestamps and corresponding address pointers, said address pointers identifying said first specified point within said first encrypted multimedia stream from which to begin decryption.  
     
     
         27 . The apparatus as in  claim 25  wherein said timestamp index is transmitted by said content provider.  
     
     
         28 . The apparatus as in  claim 26  wherein said address pointers point to I-frames within said multimedia stream.  
     
     
         29 . The apparatus as in  claim 25  further comprising: 
 timestamp index generation logic to generate said timestamp index in real time as said first encrypted multimedia stream is received from a content provider.  
 
     
     
         30 . The apparatus as in  claim 29  further comprising: 
 I-frame identification logic to identify an I-frame within said first encrypted multimedia stream by decrypting said first encrypted multimedia stream from said specified point in time until an I-frame is reached.  
 
     
     
         31 . The apparatus as in  claim 30  wherein once said I-frame identification logic identifies said I-frame, said conditional access module decrypts said first encrypted multimedia stream from said I-frame onward, said apparatus further comprising: 
 a decoder for decoding said first encrypted multimedia stream from said I-frame onward; and  
 a display for rendering said first encrypted multimedia stream.  
 
     
     
         32 . An article of manufacture including a sequence of instructions which, when executed by a machine, cause said machine to perform the operations of: 
 storing a first encrypted multimedia stream on a storage device as said stream is broadcast by a content provider;    storing a stream of conditional access data on said storage device, said stream of conditional access data associated with said multimedia stream; and    decrypting said first encrypted multimedia stream from a specified point within said encrypted multimedia stream using said stream of conditional access data, responsive to a user request to play back said encrypted multimedia stream from said specified point.    
     
     
         33 . The article of manufacture as in  claim 32  wherein decrypting further comprising: 
 reading conditional access data from said stream of conditional access data from said specified point concurrently with reading said first encrypted multimedia stream from said specified point, said conditional access data identifying successive keys for decrypting corresponding successive portions of said first encrypted multimedia stream.  
 
     
     
         34 . The article of manufacture as in  claim 33  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 providing said successive keys identified by said conditional access data to a conditional access module wherein said conditional access module uses said successive keys to decrypt corresponding successive portions of said first encrypted multimedia stream to produce a first decrypted multimedia stream.  
 
     
     
         35 . The article of manufacture as in  claim 34  including additional instructions which, when executed by said machine, cause said machine to perform the operations of:: 
 decoding said first decrypted multimedia stream using a specified codec.  
 
     
     
         36 . The article of manufacture as in  claim 35  wherein said specified codec is MPEG-2.  
     
     
         37 . The article of manufacture as in  claim 33  wherein a secure micro unit provides said successive keys to said conditional access module responsive to reading said conditional access data.  
     
     
         38 . The article of manufacture as in  claim 32  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 storing a second encrypted multimedia stream on said storage device at the same time as said first encrypted multimedia stream is stored to said storage device, wherein said stream of conditional access data contains conditional access data associated with said second encrypted multimedia stream as well as said first multimedia stream;  
 decrypting said second encrypted multimedia stream using said stream of conditional access data responsive to a user request to play back said second encrypted multimedia stream from a specified point within said second encrypted multimedia stream.  
 
     
     
         39 . The article of manufacture as in  claim 38  wherein said first and second multimedia streams are stored on said storage device in a multiplexed format.  
     
     
         40 . The article of manufacture as in  claim 39  wherein said multiplexed format comprises a series of packets containing multimedia data for said first and second multimedia streams.  
     
     
         41 . The article of manufacture as in  claim 32  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 performing a lookup in a timestamp index using a specified point in time to identify said specified point within said first encrypted multimedia stream to begin decrypting.  
 
     
     
         42 . The article of manufacture as in  claim 41  wherein said timestamp index is comprised of a set of timestamps and corresponding address pointers, said address pointers identifying said specified point within said first encrypted multimedia stream from which to begin decryption.  
     
     
         43 . The article of manufacture as in  claim 41  wherein said timestamp index is transmitted by said content provider.  
     
     
         44 . The article of manufacture as in  claim 42  wherein said address pointers point to I-frames within said multimedia stream.  
     
     
         45 . The article of manufacture as in  claim 41  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 generating said timestamp index in real time as said first encrypted multimedia stream is received.  
 
     
     
         46 . The article of manufacture as in  claim 45  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 identifying an I-frame within said first encrypted multimedia stream by decrypting said first encrypted multimedia stream from said specified point in time until an I-frame is reached.  
 
     
     
         47 . The article of manufacture as in  claim 46  including additional instructions which, when executed by said machine, cause said machine to perform the operations of: 
 decrypting and decoding said I-frame as well as any B and P frames following said I-frame; and  
 rendering said multimedia stream on a display beginning with said I-frame.  
 
     
     
         48 . A method comprising: 
 receiving a request to play back an encrypted multimedia stream stored on a mass storage device, said request including a point in time from which said encrypted multimedia stream is to be played;    performing a lookup in a timestamp index to identify an address pointer identifying a point within said encrypted multimedia stream corresponding to said point in time; and    decrypting said encrypted multimedia stream from said point within said multimedia stream.    
     
     
         49 . The method as in  claim 48  further comprising: 
 generating a timestamp index in real time as said encrypted multimedia stream is being stored on said mass storage device.  
 
     
     
         50 . The method as in  claim 48  further comprising: 
 receiving said timestamp index from a content provider providing said multimedia stream.  
 
     
     
         51 . The method as in  claim 48  further comprising: 
 if said address pointer identifies a point within said encrypted multimedia stream which is not an I-frame,  
 decrypting said encrypted multimedia stream until an I-frame is reached; and  
 decrypting, decoding and rendering said encrypted multimedia stream on a display from said I-frame onward.  
 
     
     
         52 . The method as in  claim 48  further comprising: 
 receiving a request to fast-forward through said encrypted multimedia stream; and  
 decrypting, decoding and displaying a series of I-frames in succession in response to said fast-forward request, said I-frames being decrypted, decoded and displayed at a rate based on a selected speed of said fast-forward request.  
 
     
     
         53 . The method as in  claim 52  wherein said I-frames are identified by estimating a location of a next successive I-frame; 
 jumping to said estimated location;  
 decoding said decrypted multimedia stream from said location onward until said next successive I-frame is reached; and  
 decrypting, decoding and displaying said next successive I-frame.  
 
     
     
         54 . The method as in  claim 52  further comprising: 
 decrypting I-frames as quickly as decryption keys can be generated if said selected speed of said fast forward request exceeds a maximum speed at which said decryption keys can be generated.  
 
     
     
         55 . The method as in  claim 52  further comprising: 
 jumping past one or more successive I-frames before a next I-frame is decrypted.