Watermark Stealing in Large Language Models

Fuente: arXiv
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Hauptverfasser: Jovanović, Nikola, Staab, Robin, Vechev, Martin
Format: Preprint
Veröffentlicht: 2024
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author Jovanović, Nikola
Staab, Robin
Vechev, Martin
author_facet Jovanović, Nikola
Staab, Robin
Vechev, Martin
contents LLM watermarking has attracted attention as a promising way to detect AI-generated content, with some works suggesting that current schemes may already be fit for deployment. In this work we dispute this claim, identifying watermark stealing (WS) as a fundamental vulnerability of these schemes. We show that querying the API of the watermarked LLM to approximately reverse-engineer a watermark enables practical spoofing attacks, as hypothesized in prior work, but also greatly boosts scrubbing attacks, which was previously unnoticed. We are the first to propose an automated WS algorithm and use it in the first comprehensive study of spoofing and scrubbing in realistic settings. We show that for under $50 an attacker can both spoof and scrub state-of-the-art schemes previously considered safe, with average success rate of over 80%. Our findings challenge common beliefs about LLM watermarking, stressing the need for more robust schemes. We make all our code and additional examples available at https://watermark-stealing.org.
format Preprint
id arxiv_https___arxiv_org_abs_2402_19361
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Watermark Stealing in Large Language Models
Jovanović, Nikola
Staab, Robin
Vechev, Martin
Machine Learning
Artificial Intelligence
Cryptography and Security
LLM watermarking has attracted attention as a promising way to detect AI-generated content, with some works suggesting that current schemes may already be fit for deployment. In this work we dispute this claim, identifying watermark stealing (WS) as a fundamental vulnerability of these schemes. We show that querying the API of the watermarked LLM to approximately reverse-engineer a watermark enables practical spoofing attacks, as hypothesized in prior work, but also greatly boosts scrubbing attacks, which was previously unnoticed. We are the first to propose an automated WS algorithm and use it in the first comprehensive study of spoofing and scrubbing in realistic settings. We show that for under $50 an attacker can both spoof and scrub state-of-the-art schemes previously considered safe, with average success rate of over 80%. Our findings challenge common beliefs about LLM watermarking, stressing the need for more robust schemes. We make all our code and additional examples available at https://watermark-stealing.org.
title Watermark Stealing in Large Language Models
topic Machine Learning
Artificial Intelligence
Cryptography and Security
url https://arxiv.org/abs/2402.19361