Watermarking Machine Learning Models for Theft Protection

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Solution Overview

Problem

Machine learning models, particularly those used in object detection, face challenges in protecting their training data from theft and unauthorized cloning due to the complexity of neural networks, which makes it difficult to implement effective protection without compromising low-latency and privacy requirements, especially in applications like autonomous driving.

Innovation Solution

A method for watermarking machine learning models involves modifying a subset of training images with a pixel pattern, which is then used to train the model, allowing for the detection of cloned models by overlaying the same pattern on test images and verifying the output classifications, thus providing a reliable protection mechanism without full access to the model.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ML model is stored in the cloud for security, then protection from theft is improved, but low-latency operation and user privacy are compromised

Engineering Contradiction:
Improveprotection from theftVSAvoidlow-latency operation
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The solution segments the protection mechanism into two parts: (1) the ML model operates locally on the device for low-latency and privacy preservation, and (2) a watermarking signature is embedded within the model to enable remote verification of authenticity. This segmentation allows the model to remain on-device while still providing cloud-level security through the embedded watermark.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The watermark acts as an intermediary element embedded within the ML model. It serves as a mediator that enables verification of model authenticity without requiring the model to be stored in the cloud. The watermark contains encoded information that can be extracted and verified to prove the model's origin and integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the ML model complexity is increased for better performance, then accuracy is improved, but vulnerability to extraction and cloning increases

Engineering Contradiction:
ImproveaccuracyVSAvoidvulnerability to extraction
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The solution applies preliminary anti-action by embedding a watermark into the ML model during the training phase, before the model can be extracted or cloned. This preemptive measure ensures that even if the complex model is later extracted by an adversary, the embedded watermark remains intact and can be used to verify the model's authenticity and trace its origin.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The solution changes the parameter space by embedding additional information (the watermark) within the model's weight parameters or architecture. This allows the model to maintain its complex structure for high accuracy while simultaneously carrying verification information that protects against unauthorized cloning. The watermark modifies certain parameters to encode ownership information.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the training data is protected from access, then theft prevention is improved, but the ability to verify model authenticity is worsened

Engineering Contradiction:
Improvetheft preventionVSAvoidverification of authenticity
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The solution performs preliminary action by embedding the watermark during the model training process itself, rather than requiring access to the training data after the model is trained. This allows verification of model authenticity without needing to access or analyze the original training data, thus preventing theft while maintaining verification capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The watermark acts as a copyable verification signature that can be extracted from the trained model without requiring access to the original training data. This copied verification information enables authenticity detection independently of the training data, allowing theft prevention and verification to coexist.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS12013922B2Method for watermarking a machine learning model
Publication Date: 2024.06.18 NXP BV
  • US12013922B2 patent drawing
  • US12013922B2 patent drawing
  • US12013922B2 patent drawing

AI summary

A method is provided for watermarking a machine learning model used for object detection. In the method, a first subset of a labeled set of ML training samples is selected. Each of one or more objects in the first subset includes a class label. A pixel pattern is selected to use as a watermark in the first subset of images. The pixel pattern is made partially transparent. A target class label is selected. One or more objects of the first subset of images are relabeled with the target class label. In another embodiment, the class labels are removed from objects in the subset of images instead of relabeling them. Each of the first subset of images is overlaid with the partially transparent and scaled pixel pattern. The ML model is trained with the set of training images and the first subset of images to produce a trained and watermarked ML model.