Method and System for Ensuring Sequential Playback of Digital Media
First Claim
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1. A method for requiring sequential playback of a digital media asset, said method comprising:
- (a) accessing decryption instructions associated with the digital media asset;
(b) accessing a first segment of the digital media asset;
(c) decrypting the first segment of the digital media asset with a decryption key;
(d) decoding the decrypted first segment to obtain decoded media data;
(e) outputting the decoded media data pertaining to the decrypted first segment to an output device;
(f) determining a sequential key for a next segment of the digital media asset based on at least a portion of the decoded media data pertaining to the decrypted first segment;
(g) accessing the next segment of the digital media asset; and
(h) decrypting the next segment of the digital media asset based on at least the sequential key.
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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.
271 Citations
17 Claims
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1. A method for requiring sequential playback of a digital media asset, said method comprising:
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(a) accessing decryption instructions associated with the digital media asset; (b) accessing a first segment of the digital media asset; (c) decrypting the first segment of the digital media asset with a decryption key; (d) decoding the decrypted first segment to obtain decoded media data; (e) outputting the decoded media data pertaining to the decrypted first segment to an output device; (f) determining a sequential key for a next segment of the digital media asset based on at least a portion of the decoded media data pertaining to the decrypted first segment; (g) accessing the next segment of the digital media asset; and (h) decrypting the next segment of the digital media asset based on at least the sequential key. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A media playback device, comprising:
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a storage device configured to store encrypted digital media content; a decryption engine configured to decrypt the encrypted digital media content to obtain encoded media content, the decryption of the encrypted digital media content requiring a content access key and a sequential key; a decoder configured to produce decoded data from the encoded media content; an output device configured to output the decoded data; and a sequential key generator operatively connected to said decoder and said decryption engine, said sequential key generator being configured to produce different sequential keys for use by said decryption engine in decoding each of a plurality of different segments of the encrypted digital media content. - View Dependent Claims (12, 13, 14)
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15. A system for cryptographically ensuring sequential playback of a digital media asset, said system comprising:
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means for accessing an nth segment of a digital media asset having a plurality of segments; means for decrypting at least the nth segment of the digital media asset with a decryption key; means for decoding the decrypted nth segment to obtain decoded media data; means for outputting the decoded media data pertaining to the decrypted nth segment to an output device; means for determining a sequential key for a n+1th segment of the digital media asset based on at least a portion of the decoded media data pertaining to the nth segment; means for accessing the n+1th segment of the digital media asset; and means for decrypting the n+1th segment of the digital media asset based on at least the sequential key. - View Dependent Claims (16, 17)
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Specification