Image Obfuscation with Selective Decryption Keys

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Solution Overview

Problem

Current secure image transmission methods in video surveillance are complex and costly, and existing techniques that apply total blurring do not optimally ensure the confidentiality of personal data, as they only allow authorized recipients to view entire image content.

Innovation Solution

A method involving the transmission of images with obfuscated zones and encrypted pixel values, where each receiving device is sent a unique secret key allowing decryption of only authorized areas, using a correspondence table and encryption algorithms like BSW07, CPW08, or AC17, to reconstruct a partially reconstituted image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If total blurring is applied to images for secure transmission, then confidentiality of personal data is ensured, but authorized users cannot view partial content without the key

Engineering Contradiction:
Improveconfidentiality of personal dataVSAvoidflexibility of access control
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent divides the image into multiple zones, each containing personal data about different objects. Each zone is encrypted with a unique encryption key associated with specific object types. This allows different authorized users to access only the zones relevant to their role, rather than requiring total decryption of the entire image.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different encryption keys are applied to different zones of the image based on the type of objects present. Each zone has its own security characteristics and access controls, allowing fine-grained permission management where users can access specific regions of the image based on their authorization level.

Inventive Principle:
Principle #3Local quality

2Reliability

If secure communication channels are used for image transmission, then confidentiality is maintained, but implementation complexity and cost increase

Engineering Contradiction:
Improveconfidentiality of transmitted informationVSAvoidcomplexity of secure communication implementation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the security function from the communication channel itself and implements it at the application layer through encryption. Instead of relying on secure transport protocols or encrypted channels, the image data is encrypted before transmission using multiple keys, allowing use of standard unsecured communication infrastructure while maintaining confidentiality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If all pixel values are encrypted with the same key, then decryption is simple, but authorized users cannot access only specific portions of the image

Engineering Contradiction:
Improvesimplicity of decryptionVSAvoidunauthorized access to partial content
Core Design Contradiction:
Ease of operationVSLoss of information

Solution Approach 1:

The patent segments the encryption process by applying different encryption keys to different zones of the image. Each zone corresponding to specific objects is encrypted with a key associated with that object type, allowing selective decryption of only the portions a user is authorized to view.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of encrypting the entire image with a single key (excessive action) or leaving it unencrypted (insufficient action), the patent applies partial encryption to only the zones containing personal data about specific objects, using multiple keys to enable selective access to different portions of the image.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4391526A1Methods for transmitting and receiving an image representing at least one object, electronic devices for transmitting and receiving and associated computer program products
Publication Date: 2024.06.26 THALES SA
  • EP4391526A1 patent drawingFigure 1
  • EP4391526A1 patent drawingFigure 2
  • EP4391526A1 patent drawingFigure 3

AI summary

The present invention relates to a method for transmitting, a transmitting device (20), and a method for receiving, by a receiving device (25), an image with obfuscated area(s). The transmitting method comprises applying obfuscation to identified areas of an acquired image and generating an encrypted message comprising the encrypted pixel values ​​of the identified areas in the resulting image. The transmitting method also comprises sending an individual secret key and transmitting the image with obfuscated area(s) to the receiving device. The receiving method comprises receiving the image with obfuscated area(s), the encrypted message, and the individual secret key. The receiving method also comprises partially decrypting the encrypted message and reconstructing a partially reconstructed image from the decrypted message and the received image.