Method and system for ensuring sequential playback of digital media
First Claim
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1. A method for requiring a media asset to be played back sequentially, the method comprising, at a server device:
- selecting an encryption algorithm;
dividing the media asset into a first segment and a plurality of additional segments arranged in a sequence;
generating a sequential key for each segment in the plurality of additional segments, wherein the sequential key for a particular segment in the plurality of additional segments arranged in the sequence is based, at least in part, on decoded media data included in a previous segment of the media asset immediately prior to the particular segment in the sequence;
encrypting, based on the selected encryption algorithm, each segment in the media asset in accordance with a corresponding encryption key to produce a plurality of encrypted segments, wherein the first segment is encrypted with a seed key and each particular segment in the plurality of additional segments is encrypted with the sequential key generated for the particular segment;
generating decryption information for decrypting the plurality of encrypted segments, wherein the decryption information identifies the selected encryption algorithm;
combining the plurality of encrypted segments and the decryption information to produce a protected media asset; and
storing the protected media asset,wherein the sequential keys are not included in the decryption information to cause a decryption algorithm to decrypt the plurality of encrypted segments, in an order according to the sequence, to generate the decoded media data included in each segment that is utilized to reconstruct the sequential key for a subsequent segment in the sequence.
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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.
11 Citations
20 Claims
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1. A method for requiring a media asset to be played back sequentially, the method comprising, at a server device:
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selecting an encryption algorithm; dividing the media asset into a first segment and a plurality of additional segments arranged in a sequence; generating a sequential key for each segment in the plurality of additional segments, wherein the sequential key for a particular segment in the plurality of additional segments arranged in the sequence is based, at least in part, on decoded media data included in a previous segment of the media asset immediately prior to the particular segment in the sequence; encrypting, based on the selected encryption algorithm, each segment in the media asset in accordance with a corresponding encryption key to produce a plurality of encrypted segments, wherein the first segment is encrypted with a seed key and each particular segment in the plurality of additional segments is encrypted with the sequential key generated for the particular segment; generating decryption information for decrypting the plurality of encrypted segments, wherein the decryption information identifies the selected encryption algorithm; combining the plurality of encrypted segments and the decryption information to produce a protected media asset; and storing the protected media asset, wherein the sequential keys are not included in the decryption information to cause a decryption algorithm to decrypt the plurality of encrypted segments, in an order according to the sequence, to generate the decoded media data included in each segment that is utilized to reconstruct the sequential key for a subsequent segment in the sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A non-transitory computer readable storage medium configured to store instructions that, when executed by a processor included in a computing device, cause the computing device to carry out steps that include:
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selecting an encryption algorithm; dividing a media asset into a first segment and a plurality of additional segments arranged in a sequence; generating a sequential key for each segment in the plurality of additional segments, wherein the sequential key for a particular segment in the plurality of additional segments arranged in the sequence is based, at least in part, on decoded media data included in a previous segment of the media asset immediately prior to the particular segment in the sequence, wherein the first segment is encrypted with a seed key and each particular segment in the plurality of additional segments is encrypted with the sequential key generated for the particular segment; encrypting each segment in the media asset in accordance with a corresponding encryption key to produce a plurality of encrypted segments; generating decryption information for decrypting the plurality of encrypted segments, wherein the decryption information identifies the selected encryption algorithm; combining the plurality of encrypted segments and the decryption information to produce a protected media asset; and storing the protected media asset, wherein the sequential keys are not included in the decryption information to cause a decryption algorithm to decrypt the plurality of encrypted segments, in an order according to the sequence, to generate the decoded media data included in each segment that is utilized to reconstruct the corresponding sequential key for a subsequent segment in the sequence. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A computing device, comprising:
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a processor configured to cause the computing device to carry out steps that include; selecting an encryption algorithm; dividing a media asset into a first segment and a plurality of additional segments arranged in a sequence; generating a sequential key for each segment in the plurality of additional segments, wherein the sequential key for a particular segment in the plurality of additional segments arranged in the sequence is based, at least in part, on decoded media data included in a previous segment of the media asset immediately prior to the particular segment in the sequence, wherein the first segment is encrypted with a seed key and each particular segment in the plurality of additional segments is encrypted with the sequential key generated for the particular segment; encrypting each segment in the media asset in accordance with a corresponding encryption key to produce a plurality of encrypted segments; generating decryption information for decrypting the plurality of encrypted segments, wherein the decryption information identifies the selected encryption algorithm; combining the plurality of encrypted segments and the decryption information to produce a protected media asset; and storing the protected media asset, wherein the sequential keys are not included in the decryption information to cause a decryption algorithm to decrypt the plurality of encrypted segments, in an order according to the sequence, to generate the decoded media data included in each segment that is utilized to reconstruct the corresponding sequential key for a subsequent segment in the sequence. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification