Method of broadcasting multimedia content via distribution network

• US 20060156377A1
• Filed: 06/23/2004
• Published: 07/13/2006
• Est. Priority Date: 07/04/2003
• Status: Active Grant

• Current Assignee: III Holdings 6, LLC
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Gentric, Philippe
• Granted Patent: US 7,912,218 B2
• Time in Patent Office: Days
• US Class Current: 725/138
• CPC Class Codes: H04N 21/26613 for generating or managing keys in general key distribution for secret or secure communication involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] H04L9/083; network support of key management H04L63/06; key management for network security in communication control or processing H04W12/04
• CPC Class Codes: H04N 21/63345 by transmitting keys key distribution for secret or secure communication H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 21/8456 by decomposing the content in the time domain, e.g. in time segments
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58
• CPC Class Codes: H04N 7/17318 Direct or substantially direct transmission and handling of requests

Abstract

The invention proposes to divide a content to be transmitted via a network into a set of slices and to generate a set of files from this set of slices. The slices (or the files) are encrypted before downloading in such a way that the client cannot use the slice (or the file) before having acquired the associated decryption key. The invention thereby allows protecting a downloaded content on a slice-by-slice basis (or on a file-by-file basis) rather than protecting a downloaded content as a whole. The transmission (in download mode) between the server and the client is ruled by the HTTP protocol that is accepted by all firewalls and NAT. Consequently, the transmitted content is accessible for any client device that has access to the Web without restriction. Advantageously, the slices can be decoded independently of each other.

Claims

1. A system comprising at least:

a source (1) for acquiring a multimedia content,

an encoder (5) for encoding said multimedia content,

a slicer (6) for slicing said encoded multimedia content into at least one set of slices, and for providing at least one set of files from said at least one set of slices, said slicer implementing an encryption algorithm, such that at least the slice contained in a file cannot be used without a decryption key associated therewith,

a distribution network (10),

an access provider (12) for providing a client device (14) with an access to said distribution network,

a content server (8) linked to said distribution network and having access to said set or sets of files for downloading at least one of said files to said client device via said distribution network upon reception of a request from said client device, and

a key server linked to said distribution network for providing said client device with the decryption key or keys that are associated with the downloaded files.

2. A system as claimed in claim 1, wherein a decryption key is provided to said client device upon successful downloading of the file or files it is associated with.

3. A system as claimed in claim 1, wherein slices are generated in such a way that they can be decoded independently of each other.

4. A content server (8) having access to at least one set of files (Si) generated by slicing an encoded multimedia content into at least one set of slices and providing at least one set of files (f_i,j) from said at least one set of slices by implementation of an encryption algorithm such that at least the slice contained in a file cannot be used without a decryption key associated therewith,

said content server having means for downloading to a client device (14) at least one of said files upon reception of a request from said client device.

5. A content server as claimed in claim 4, wherein said files originate from slices that can be decoded independently of each other.

6. A content server as claimed in claim 4, having means for sending a notification to a key server upon successful downloading of a file to said client device so that said key server provides said client device with the decryption key associated with said file.

7. A content server as claimed in claim 4, wherein said downloading means comprise:

means for sending a document to said client device upon reception of said request, said document causing said client device to repetitively send a fetching request designating said encoded multimedia content,

means for selecting which file is to be downloaded amongst said set or sets of files, upon reception of said fetching requests from said client device,

means for downloading the selected file.

8. A client device having:

means for connection to a content server, said content server having access to at least one set of files (S_i) generated by slicing an encoded multimedia content into at least one set of slices, each file containing a slice, and by implementing an encryption algorithm, such that at least the slice contained in a file cannot be used without a decryption key associated therewith, said content server offering to download at least part of said encoded multimedia content on a file-by-file basis,

means for repeatedly sending to said content server a request directed to said encoded multimedia content,

means for receiving one of said files in response to each request,

means for acquiring the decryption key associated with each file,

means for decrypting and playing said files.

9. A client device as claimed in claim 8, further comprising means for sending a subsequent request before the end of the playback of the current file.

10. A method of transmitting an encoded multimedia content to a client device, said method comprising the steps of:

encoding a multimedia content,

slicing said encoded multimedia content into at least one set of slices and providing at least one set of files from said at least one set of slices, said slicing step including an encryption step, such that at least the slice contained in a file cannot be used without a decryption key associated therewith,

downloading at least one of said files to said client device via said distribution network upon reception of a request from said client device.