System and method for secured scrambling of audio flux

• US 20050185793A1
• Filed: 03/29/2005
• Published: 08/25/2005
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: OL Security LLC (Intellectual Ventures LLC)
• Original Assignee: Medialive (Kudelski SA)
• Inventors: LeComte, Daniel, Parayre-Mitzova, Daniela
• Granted Patent: US 7,630,492 B2
• Time in Patent Office: Days
• US Class Current: 380/33
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: H04K 1/00 Secret communication

Abstract

A process for distributing digital audio sequences according to a nominal flux format including a succession of fields, each of which includes at least one digital block clusterizing a selected number of coefficients corresponding to single audio elements that are digitally coded inside the flux and utilized by audio decoders that are able to play it to be able to decode it correctly, including a preparatory step including modifying at least one of the coefficients, and a transmission step including a primary flux in compliance with a nominal format including blocks that were modified during the preparatory step and by a route separated from the primary flux by an additional piece of digital information which allows reconstruction of the original flux starting with a calculation, on recipient equipment, as a function of the primary flux and of the additional information.

Claims

1. A process for distributing digital audio sequences according to a nominal flux format comprising a succession of fields, each of which comprises at least one digital block clusterizing a selected number of coefficients corresponding to single audio elements that are digitally coded inside the flux and utilized by audio decoders that are able to play it to be able to decode it correctly, comprising:

a preparatory step comprising modifying at least one of the coefficients, and

a transmission step comprising;

a primary flux in compliance with a nominal format comprising blocks that were modified during the preparatory step and

by a route separated from the primary flux by an additional piece of digital information which allows reconstruction of the original flux starting with a calculation, on recipient equipment, as a function of the primary flux and of the additional information.

2. The process according to claim 1, wherein the primary modified flux is recorded on the recipient equipment prior to transmission of the additional information onto the recipient equipment.

3. The process according to claim 1, wherein the primary modified flux and the additional information are transmitted together in real time.

4. The process according to claim 1, wherein modification of the original flux applies to at least one structured digital audio field.

5. The process according to claim 1, wherein modifications are carried out in such that the modified primary flux is of the same size as the original digital flux.

6. The process according to claim 1, wherein the nominal flux format is defined by a coder that is common to a community of users.

7. The process according to claim 1, further comprising an analysis step for at least one part of the original flux, where the analysis step determines the nature of the modifications of the coefficients.

8. The process according to claim 7, wherein the analysis step determines the modification of the coefficients by taking into consideration concrete structure of at least one part of the original flux.

9. The process according to claim 1, wherein the modification is applied to at least a first scale factor of at least one field.

10. The process according to claim 1, wherein the modification is applied to at least one spectral coefficient of at least one field.

11. The process according to claim 1, further comprising a prior analog/digital conversion step in a structured format, where the process is applied to a digital audio signal.

12. The process according to claim 1, wherein flux comprises at least one audio field that is structured according to one of the compression formats comprising an MPEG-2 layer 3, AAC, CELP, HVXC, HILN and AC-3 formats.

13. The process according to claim 1, wherein the additional modification information comprises at least one digital routine designed to execute a function.

14. The process according to claim 1, wherein the additional modification information is subdivided into at least two sub-parts.

15. The process according to claim 14, wherein the sub-parts of the additional modification information can be distributed by different media.

16. The process according to claim 14, wherein sub-parts of the additional modification information can be distributed by the same media.

17. The process according to claim 1, wherein the additional information is transmitted through a physical vector.

18. The process according to claim 1, wherein the additional information is transmitted online.

19. A process for restoring digital audio sequences encoded according to a process according to claim 1, comprising decoding a primary flux by applying a reconstruction function using the additional information originating from a route separate from the vector of the primary flux, and decoding the flux reconstructed by a process adapted to the nominal format.

20. The process according to claim 1, wherein the reconstituted flux originating from the modified primary flux and the additional information is strictly identical to the original flux.

21. A system for distributing digital audio sequences according to a nominal flux format comprising an encoder according to a nominal format and a transmitter that transmits a digital flux, a means of processing an original flux that modifies at least one coefficient of the primary flux, and a means for transferring additional information corresponding to the modification.

22. Equipment for restoring digital audio sequences according to a nominal flux format comprising a decoder according to the nominal format, a means of receiving a digital flux, a means of receiving an additional piece of information associated with the primary flux, and a means for reconstructing the original flux by processing the primary flux and the additional piece of information.