Method and system for ensuring sequential playback of digital media

Abstract

Techniques for ensuring that media playback proceeds sequentially through media content of a digital media asset are disclosed. In one embodiment, distinct portions (e.g., segments) of a digital media asset can be separately encrypted such that on playback decoded data being output from at least one prior portion can be used to derive a cryptographic key that is used in decrypting a subsequent portion of the digital media asset.

1 . A method for decrypting a digital media asset, the method comprising:
 receiving the digital media asset,   wherein the digital media asset comprises a first encrypted segment and a second encrypted segment;   decrypting, by a first decryption key, the first encrypted segment to produce a first decrypted segment;   decoding the first decrypted segment to produce a first decoded segment;   generating a second decryption key based on the first decoded segment; and   decrypting, by the second decryption key, the second encrypted segment to produce a second decrypted segment.   
     
     
         2 . The method of  claim 1 , wherein the second decryption key is decrypted only when the first decoded segment is played back. 
     
     
         3 . The method of  claim 1 , further comprising:
 decoding the second decrypted segment to produce a second decoded segment.   
     
     
         4 . The method of  claim 1 , wherein receiving the digital media asset comprises receiving an encrypted digital media asset. 
     
     
         5 . The method of  claim 4 , wherein decrypting the first encrypted segment, by the first decryption key, comprises accessing decryption information related to the digital media asset. 
     
     
         6 . The method of  claim 5 , wherein the decryption information defines:
 the first decryption key; and   segment positions within the digital media asset that separate at least the first encrypted segment from the second encrypted segment.   
     
     
         7 . The method of  claim 5 , wherein the decryption information provides information related to the decrypting the first encrypted segment and the second encrypted segment in a sequential manner. 
     
     
         8 . A method for encrypting a digital media asset, the method comprising:
 obtaining the digital media asset, wherein the digital media asset comprises a first segment and a second segment;   generating, by an encrypting algorithm, a first encryption key and a second encryption key for the first segment and the second segment, respectively, wherein the second encryption key is generated based on the first segment;   encrypting, by the first encryption key, the first segment to produce a first encrypted segment;   encrypting, by the second encryption key, the second segment to produce a second encrypted segment; and   providing the digital media asset to at least one computing device.   
     
     
         9 . The method of  claim 8 , further comprising:
 generating decryption information with the digital media asset, wherein the decryption information defines:
 the first encryption key, and 
 segment positions within the digital media asset that separate at least the first encrypted segment from the second encrypted segment. 
   
     
     
         10 . The method of  claim 9 , wherein the second segment is generated sequentially with respect to the first segment. 
     
     
         11 . The method of  claim 9 , further comprising:
 segregating the digital media asset to form the first segment and the second segment.   
     
     
         12 . The method of  claim 9 , wherein the decryption information comprises a decryption algorithm to be used by the at least one computing device to sequentially decrypt the first segment and the second segment. 
     
     
         13 . The method of  claim 12 , further comprising:
 encrypting, by a second encryption algorithm, the digital media asset and the decryption information.   
     
     
         14 . The method of  claim 8 , wherein the second encryption key is determined based on decoded data provided by the first segment. 
     
     
         15 . At least one non-transitory computer readable storage medium configured to store instructions that, when executed by at least one processor included in a computing device, cause the computing device to decrypt a digital media asset, by carrying out steps that include:
 receiving the digital media asset, wherein the digital media asset comprises a first encrypted segment and a second encrypted segment;   decrypting, by a first decryption key, the first encrypted segment to produce a first decrypted segment;   decoding the first decrypted segment to produce a first decoded segment;   generating a second decryption key based on the first decoded segment; and   decrypting, by the second decryption key, the second encrypted segment to produce a second decrypted segment.   
     
     
         16 . The at least one non-transitory computer readable storage medium of  claim 15 , wherein the second decryption key is decrypted only when the first decoded segment is played back. 
     
     
         17 . The at least one non-transitory computer readable storage medium of  claim 15 , wherein the steps further include:
 decoding the second decrypted segment to produce a second decoded segment.   
     
     
         18 . The at least one non-transitory computer readable storage medium of  claim 15 , wherein receiving the digital media asset comprises receiving an encrypted digital media asset. 
     
     
         19 . The at least one non-transitory computer readable storage medium of  claim 18 , wherein decrypting the first encrypted segment, by the first decryption key, comprises accessing decryption information related to the digital media asset. 
     
     
         20 . The at least one non-transitory computer readable storage medium of  claim 19 , wherein the decryption information defines:
 the first decryption key; and   segment positions within the digital media asset that separate at least the first encrypted segment from the second encrypted segment.