PolyJuice Makes It Real: Black-Box, Universal Red-Teaming for Synthetic Image Detectors

Sepehr Dehdashtian*, Mashrur M. Morshed*, Jacob H. Seidman, Gaurav Bharaj, Vishnu N. Boddeti

NeurIPS 2025

Why Is Red Teaming Important?

Red-Teaming Setting

Intuition Behind PolyJuice

distribution shift

PolyJuice Overview

Average image of professions
\( \underset{\mathbf{U}}{\argmax}\ \ \text{Tr}\Big\{\mathbf{U}^\top \mathbf{Z} \mathbf{H} \mathbf{K}_{\mathbf{YY}} \mathbf{H} \mathbf{Z}^\top \mathbf{U}\Big\} \\ \text{s.t.} \quad \mathbf{U}^\top \mathbf{U} = \mathbf{I} \)
\( h_{\mathbf{\delta_t}}(\mathbf{z}'_t) = \mathbf{z}'_t + \lambda_t \mathbf{\delta_t},\quad t=1, \ldots, T-1\)

Steering Visualization

steering visualization

How Successful is PolyJuice in Attacking Synthetic Image Detectors?

Average image of professions

How Effective is PolyJuice When Applied on a T2I Model-Specific Detector?

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How Effective is PolyJuice in Reducing False Negative Rate of Existing SIDs?

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How Transferable are the Directions from Lower to Higher Resolutions?

\( \delta_{\text{low}} \in \mathbb{R}^{C \times H_{\text{low}} \times W_{\text{low}} } \longrightarrow \delta_{\text{high}} \in \mathbb{R}^{C \times H_{\text{high}} \times W_{\text{high}}} \) Average image of professions

How Does PolyJuice Affect the Spectral Fingerprint of the T2I Models?

Average image of professions

Does PolyJuice Conserve Image Quality?

Average image of professions Average image of professions

Summary

  • PolyJuice:
    • is a novel black-box and distribution-based red-teaming method against SIDs,
    • is a brew once, break many approach,
    • improves the rate of deceiving SID by up to 84%,
    • steers samples into failure regions underexplored by standard T2I generation,
    • improves robustness of SIDs by up to 30% when attacks are used to fine-tune them.