Overview
The paper introduces SRAF, a framework designed for stealthy and robust adversarial fingerprinting aimed at copyright verification of Large Language Models (LLMs). This framework addresses challenges associated with protecting Intellectual Property (IP) in LLMs amid increasing model theft and unauthorized commercialization. SRAF functions as a black-box solution for ownership verification, distinguishing itself from prior methods by improving resilience against various model alterations and detection strategies.
Research Context
Protection of Intellectual Property for Large Language Models is identified as a critical concern due to the escalation of model theft and unauthorized commercialization. Adversarial fingerprinting is presented as a promising black-box solution for ownership verification. However, existing methods in this domain reportedly suffer from significant limitations:
- Fragility against downstream model modifications.
- Sensitivity to system prompt variations.
- Easy detectability stemming from high-perplexity input patterns.
Approach
The proposed SRAF framework integrates two primary techniques to overcome the identified limitations:
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Synergistic Joint Optimization Strategy
SRAF employs a synergistic joint optimization strategy across homologous model variants and diverse chat templates. This strategy is designed to force the fingerprint to anchor onto the invariant intrinsic comprehension features of the model family.
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Perplexity Hiding Technique
A Perplexity Hiding technique is introduced. This method embeds adversarial perturbations specifically within Markdown tables. The purpose of this embedding is to effectively align the prompt's statistics with natural language, thereby evading perplexity-based detection mechanisms.
Findings
Extensive experiments were conducted to evaluate SRAF across multiple model families and parameter scales. The results indicated that SRAF significantly enhanced robustness across several modification types:
- Fine-tuning
- Alignment
- Pruning
- Merging
- Input perturbations
Beyond robustness, the framework also demonstrated exceptional stealthiness. Furthermore, SRAF maintained low false-positive rates. These experimental outcomes suggest that SRAF offers a practical and resilient black-box solution for LLM ownership verification.
Why This Matters
The escalating issues of model theft and unauthorized commercialization of Large Language Models highlight a critical need for Intellectual Property protection. SRAF provides a practical and resilient black-box solution for ownership verification, addressing existing methods' fragility and detectability.