Neural Network Bit-Wise Correlation for Side Channel Key Recovery

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Solution Overview

Problem

Current methods for training neural networks to enhance correlation coefficients in side channel attacks are limited in effectively utilizing profiling traces and loss functions to determine secret keys, particularly in cryptographic systems.

Innovation Solution

A method involving a neural network, such as a convolutional neural network, is trained using profiling traces of physical parameters like electrical power consumption, with a bit-wise correlation loss function and weighting coefficients to improve correlation coefficients, enabling the determination of secret keys in cryptographic systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional loss functions are used for training neural networks in side channel attacks, then training is simpler, but correlation coefficient is lower

Engineering Contradiction:
Improvecorrelation coefficientVSAvoidloss function complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The loss function is segmented into bit-wise components, where each bit of the intermediate value is processed separately. This segmentation allows the neural network to learn precise bit-level correlations from profiling traces, thereby increasing the correlation coefficient while maintaining manageable complexity through modular bit-level processing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the parameter representation by using bit-wise decomposition of the intermediate values. Instead of treating intermediate values as continuous or whole units, the loss function operates on individual bits, transforming the parameter space to enable more precise correlation measurement and improve attack effectiveness

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If more profiling traces are collected, then training accuracy improves, but measurement time increases

Engineering Contradiction:
Improvetraining accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention extracts only the essential bit-level features from profiling traces that are most relevant to key recovery. By focusing on specific bit correlations rather than processing entire intermediate values, the method achieves high training accuracy with fewer traces, reducing measurement time while maintaining effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bit-wise loss function applies partial action by selectively correlating specific bits of intermediate values with power consumption traces. This partial correlation approach achieves sufficient training accuracy without requiring complete analysis of all trace data, thereby reducing the time needed for data collection and processing

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If bit-wise correlation loss function is used, then correlation coefficient increases, but computational complexity increases

Engineering Contradiction:
Improvecorrelation coefficientVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The computational complexity is managed through segmentation of the loss function into independent bit-wise operations. Each bit correlation can be computed separately and efficiently, allowing parallel processing that reduces overall computational burden while maintaining high correlation coefficients through precise bit-level matching

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By changing to bit-wise parameter representation, the invention transforms complex continuous optimization into discrete bit-level correlation tasks. This parameter transformation simplifies the computational structure despite the increased precision, as bit-wise operations are computationally more efficient than continuous value matching

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20220114422A1Method and apparatus for a neural network
Publication Date: 2022.04.14 ROBERT BOSCH GMBH
  • US20220114422A1 patent drawing
  • US20220114422A1 patent drawing
  • US20220114422A1 patent drawing

AI summary

A computer-implemented method for a neural network, for example an artificial deep neural network. The method includes: providing a plurality of training data sets, each training data set comprising input data for the neural network and associated output data, training the neural network based on the plurality of training data sets and a loss function, wherein the loss function is based on a bit-wise correlation of an output value provided by the neural network and a predetermined function characterizing an operation of a physical system.