System, method, and device for playing back recorded content
View Patent ↗A secure software package for original equipment manufacturers to run in electronic devices in order to access and dynamically decrypt encrypted audio video or other content from a memory storage device such as a memory card, optical or hard disk such that the user interface of the device need only send simple commands and the decrypted content is output.
1. A device for playback of encrypted audio and/or video tracks from a memory card, wherein an audio and/or video track comprises one or more than one audio and/or video file, the audio and/or video file being retrievable in a plurality of portions, the device comprising:
a processor; and
a module operatively coupled with the processor and configured, for each audio and/or video file within an audio and/or video track, for:
obtaining an encrypted key from a protected area of the memory card;
retrieving one of the plurality of portions of the audio and/or video file from the memory card;
decrypting the obtained encrypted key;
decrypting the one of the plurality of portions of the audio and/or video file with the decrypted key; and
deleting the decrypted key after decrypting the one of the plurality of portions of the audio and/or video file before decrypting an additional one of the plurality of portions of the audio and/or video file.
2. The device of claim 1 , wherein the module is configured to retrieve and decrypt about two seconds of the audio and/or video file at a time with the decrypted key before the decrypted key is deleted.
3. The device of claim 1 , wherein the device comprises a personal computer or a portable device having a processor.
4. The device of claim 1 , wherein for each additional one of the plurality of portions, the module is configured to:
decrypt the encrypted key;
decrypt the additional one of the plurality of portions of the audio and/or video file with the decrypted key; and
delete the decrypted key after decrypting the additional one of the plurality of portions of the audio and/or video file before decrypting a next additional one of the plurality of portions of the audio and/or video file.
5. The device of claim 4 , wherein the module is further configured to:
store the encrypted key in a memory of the device; and
for each additional one of the plurality of portions of the audio and/or video file, decrypt the encrypted key stored in the memory of the device.
6. The device of claim 1 , wherein the encrypted key comprises an encrypted title key and wherein the module is configured to decrypt the encrypted key by calculating a media unique key and decrypting the encrypted title key stored in a memory of the device with the media unique key.
7. The device of claim 1 , wherein the module is further configure to play back to a user each one of the plurality of portions of the audio and/or video file as each one of the plurality of portions of the audio and/or video file is decrypted.
8. A non-volatile computer readable storage device having an executable program, the program to be utilized in an audio and/or video device for playback of encrypted tracks of audio and/or video content, wherein an encrypted track of audio and/or video content comprises at least one encrypted audio or video file, the program configured to, for each encrypted audio or video file:
decrypt an encrypted audio or video file from a memory card, wherein decrypting the audio or video file comprises:
(a) decrypting a key stored in a memory of the audio and/or video device;
(b) decrypting one of a plurality of portions of the audio or video file;
(c) deleting the decrypted key; and
(d) repeating (a) through (c) until all of the plurality of portions of the audio or video file are decrypted.
9. A method for playback of audio and/or video tracks comprising one or more encrypted audio and/or video files stored on a memory card, the method comprising:
obtaining an encrypted key from a protected area of the memory card with a device having a processor and a memory operatively connected with the processor;
retrieving a first of a plurality of portions of an audio and/or video file from the memory card with the device, wherein the audio and/or video file comprises at least a portion of an audio and/or video track;
decrypting the encrypted key;
decrypting the first of the plurality of portions of the audio and/or video file with the decrypted key; and
deleting the decrypted key from the device after decrypting the first of the plurality of portions of the audio and/or video file before decrypting a next portion of the plurality of portions of the audio and/or video file.
10. The method of claim 9 , wherein retrieving the first of the plurality of portions of the audio and/or video file comprises retrieving about two seconds of the audio and/or video file.
11. The method of claim 9 , wherein the device comprises a personal computer or a portable device having a processor.
12. The method of claim 9 , wherein for the next portion of the plurality of portions of the audio and/or video the method further comprises:
decrypting the encrypted key;
decrypting the next portion of the plurality of portions of the audio and/or video file with the decrypted key; and
deleting the decrypted key after decrypting the next portion of the plurality of portions of the audio and/or video file.
13. The method of claim 12 , wherein obtaining the encrypted key from the protected area of the memory card further comprises storing the encrypted key in the memory of the device; and
wherein, for the next portion of the plurality of portions of the audio and/or video file, the step of decrypting the encrypted key comprises decrypting the encrypted key stored in the memory of the device.
14. The method of claim 9 , wherein the encrypted key comprises an encrypted title key and wherein decrypting the encrypted key comprises:
calculating a media unique key; and
decrypting the encrypted title key with the media unique key.
15. The method of claim 14 , wherein deleting the decrypted key comprises deleting the decrypted title key and the media unique key.
16. The method of claim 9 , wherein retrieving the first of the plurality of portions comprises retrieving a portion of the audio and/or video file comprising less than about 10 seconds of playback.
17. The method of claim 9 , further comprising:
retrieving information relating to audio and/or video files stored on the memory card prior to decrypting any portion of an audio and/or video file.
18. The method of claim 17 wherein retrieving information relating to audio and/or video files stored on the memory card comprises retrieving playlist information for the audio and/or video files.
19. The method of claim 18 , wherein retrieving playlist information comprises retrieving at least one of:
a name of a playlist;
a playlist name string length;
a playback time of the playlist;
tracks comprised by the playlist; and
an index corresponding to the playlist.
20. The method of claim 17 wherein retrieving information relating to audio and/or video files stored on the memory card comprises retrieving track information for the audio and/or video files.
21. The method of claim 20 wherein retrieving track information comprises retrieving:
a track number;
an index corresponding to the track number;
a number of track units in a track corresponding to the track number; and
a playback time of the track.
22. A device for playback of encrypted content from a memory card, wherein the content is retrievable as one or in successive portions of a file in a track and the file has a plurality of portions, the device comprising:
a processor; and
a module operatively coupled to the processor and configured to play the content by:
retrieving the content one portion at a time and for each portion retrieved:
obtaining an encrypted key from a protected area of the memory card;
decrypting the obtained encrypted key;
decrypting the portion of the content with the decrypted key; and
deleting the decrypted key after decrypting the portion of the content and before decrypting any succeeding portion of the content,
wherein the content is decrypted one retrieved portion at a time, each portion individually decrypted by a separate key.
23. A device as in claim 22 , wherein retrieving of the portions includes determining how to apportion the content for the retrieval of portions, the determination being based on criteria.
24. A device as in claim 23 , wherein the content is an audio, video or audiovisual file and the criteria is a predetermined fraction of file play time.