Method and system for key insertion for stored encrypted content
AssigneeSony Corporation
InventorRobert Allan Unger
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Abstract
An encrypted content transport stream is received by a viewer's device and recorded for subsequent playback. During recording, keys in headers of packets of the stream are stripped and placed in sequence in a table. Also, the table indicates changes in key indicating bits. When it is desired to play the content, start-of-frame indicator bits such as PUSI and/or RAI bits are used to access the table of keys to retrieve the keys necessary to decrypt the transport stream packets sought to be played.
Claims31
A method for playing content embodied in a transport stream, at least portions of the content being received in an encrypted form, comprising:
- establishing at least one table of keys received in the transport stream;
- for at least one packet of the transport stream, decrypting the packet and playing the packet at least in part by:
- accessing the table to identify at least one key associated with the packet;
- and
- using the key to decrypt the content.
A playback device, comprising:
- at least one content store configured for holding encrypted content, the content including a transport stream of content data packets, at least one packet containing at least one key;
- and
- at least one processor accessing the store and programmed with logic to:
- arrange the key in a key table;
- and
- link keys in the table with key changes in the transport stream, to facilitate subsequent decryption and playback of the content.
A system for providing to viewers trick playback of encrypted content, comprising:
- at least one content provider transmitting at least one encrypted transport stream;
- at least one viewer device receiving the transport stream, stripping encryption keys therefrom, and linking the keys to corresponding packets of the transport stream, such that subsequent decryption and trick mode playback is facilitated.
A computer program device, comprising:
- means for establishing at least one table of keys received in a transport stream;
- means for linking the keys to changes in encryption-indicating bits in the transport stream;
- means for, for at least one packet of the transport stream, decrypting the packet and playing the packet at least in part by:
- accessing the table to identify at least one key associated with the packet;
- and
- using the at least one key to decrypt the content.
Dependencies are inferred from the claim text.