US 2010/0303235 A1Published application

Method Providing the Means for Recognizing the Origin and/or Content of an RF Signal

AssigneeThales

InventorJean-Louis Damidaux

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Abstract

The subject of the present invention is a method providing the means for recognizing the origin and/or the content of an RF signal without requiring substantial computation means, these recognition means being accessible only to authorized persons and being practically nonmodifiable and very difficult to detect by unauthorized persons, and this being so in various applications using RF signals transmitting information that is at least partly hidden. This method is characterized in that it spreads an item of information to be hidden with the aid of a hidden code, that it distributes, with the aid of an Exclusive OR function the information thus obtained in codes that are known with the aid of a hidden distribution algorithm, that, on reception, it applies the algorithm that is the inverse of that having served for the distribution in order to gain access to the spread code, that is correlates this spread code with the hidden code in order to find the hidden information.

Claims15

Dependent claims

A method making it possible to recognize the origin and/or the content of an RF signal (10), the RF signal consisting of the sum of at least two modulated codes (7, 8), comprising:

a spread of an item of information (3) to be hidden with the aid of a hidden code (4) in order to obtain a modulated hidden code (6),
wherein the method distributes the modulated hidden code (6) in the RF signal (10) by replacing zero elements of the RF signal (10) with elements of the modulated hidden code (6), the locations of the elements to be replaced of the RF signal and the elements of the modulated hidden code (6) being determined according to a hidden algorithm (9) associated with a linear combination of the codes (7) and (8),
wherein, on reception, the method applies the algorithm (12) that is the inverse of that having served for the distribution and the same linear combination in order to gain access to the elements of the modulated hidden code, and
the method correlates this modulated hidden code with the hidden code (14) in order to find the hidden information (17).

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 12/675,532Filed 5 Sep 2008
Priority: FR 07 0664321 Sep 2007
Published: 2 Dec 2010
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G01S 19/02
Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting…:…
H04L 9/0891
Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords: revocation or update of secret…
H04L 9/3247
Including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity…:…
H04L 2209/16
Additional information or applications relating to cryptographic mechanisms or cryptographic arrangements for secret or secure communication…