Terminal Image Processing Security via Dynamic Parameter Switching
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Solution Overview
Problem
Existing image processing methods in terminals, especially 'white box' environments, are vulnerable to attacks where attackers can access intermediate data, allowing them to deduce optimal parameter values and compromise security by producing high-quality output data.
Innovation Solution
A method that dynamically sets image processing parameters to different values based on whether the input proof data matches a secret reference, using a pseudo-random function to generate intermediate data, and applying circular permutations and truncations to complicate reverse engineering and ensure degraded output when incorrect data is input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optimal parameter values are used in image processing, then output data quality is improved, but security is worsened because attackers can deduce these values through reverse engineering
Solution Approach 1:
The patent applies dynamics by making parameter values changeable rather than fixed. The system dynamically selects parameter values from multiple alternatives based on security requirements, preventing attackers from reverse-engineering single optimal values. This is achieved through storing multiple parameter sets and selectively applying them during image processing operations.
Solution Approach 2:
The patent directly applies parameter changes by modifying parameter values used in image processing functions. Instead of using fixed optimal parameters, the system varies parameter values (such as block sizes, transformation types, or quantization levels) to prevent attackers from deducing the true optimal values while maintaining acceptable output quality.
2Reliability
If parameter values are changed to prevent deduction, then security is improved, but output data quality is worsened
Solution Approach 1:
The patent applies partial action by using parameter values that are not fully optimized for quality but are sufficient to maintain acceptable output while providing security. By using multiple parameter sets where none are perfectly optimal, the system achieves a balance between security and quality, preventing attackers from deducing true optimal values while maintaining functional output.
Solution Approach 2:
The patent applies the composite principle by combining multiple parameter sets into a unified security-quality balance. Instead of relying on a single parameter configuration, the system integrates multiple parameter alternatives, selecting or combining them to achieve both security (preventing deduction) and acceptable output quality simultaneously.
3Reliability
If multiple parameter values are used, then security against reverse engineering is improved, but device complexity is worsened
Solution Approach 1:
The patent applies segmentation by dividing the parameter space into multiple discrete sets or alternatives. Each parameter set represents a segmented portion of the overall parameter space, making it harder for attackers to reverse-engineer the true values while keeping each individual segment manageable. This segmentation is implemented through storing multiple parameter configurations in memory.
Solution Approach 2:
The patent applies universality by designing a parameter management system that handles multiple parameter values through a unified framework. The same image processing functions and data structures are used regardless of which parameter set is active, allowing the system to support multiple parameter values without proportionally increasing complexity. The parameter selection mechanism serves multiple security functions simultaneously.
Data Source
AI summary
The present invention relates to a method for processing an image executed by a terminal (1), comprising steps of receiving a proof datum previously input by a user of the terminal (1), setting (104, 106) of at least one parameter to a first value when the proof datum is equal to a secret reference datum, and to a second value different to the first value when the proof datum is different to the secret reference datum, and generation (200) of an output datum from an input datum being or dependent on an image previously acquired by a sensor (4), and also from the parameter, the output datum having a value as function of the value the parameter has been set to.