Defense suite for persona skills: online sanitization, post-hoc adversarial obfuscation, and semantic backdoor watermarking¶

Strategy · All strategies
Evidence · 2 claims (2 for) · 1 study (1 design), q2 · 0 of 1 report an effect size · 2 claims rest on one study

Description¶

AntiSkillBench designs and evaluates four defense configurations intervening at different stages of the persona-skill lifecycle, covering "online versus post-hoc intervention and active risk suppression versus passive backdoor protection". Privacy Sanitization rewrites user queries online to remove private cues while preserving task intent; Adversarial Obfuscation appends conflicting private attributes post-hoc to mislead distillation; Semantic-level Backdoor Injection implants semantic watermarks in both settings so unauthorized skill reuse can later be traced.

Design Implications¶

Context¶

Requirements¶

• The defender can only intervene on the trace side before distillation, transforming or augmenting the traces without modifying the distillation function, the agent, or the deployed skill-use interface

Constraints¶

• Active defenses primarily suppress surface-level communication cues while leaving deeper background and personality information exposed; backdoor-based protection degrades under persona-centric abstraction

Target Learners¶

• LLM-based agent systems and their developers

Target Learning Goals¶

• Protecting distilled persona skills against privacy leakage, impersonation, and unauthorized reuse

Claims¶

• Active defenses (Privacy Sanitization, Adversarial Obfuscation) reduce but do not eliminate persona-skill leakage, leaving personality and background exposed [+W]
• Passive backdoor defense (SBD) effectiveness is distillation-dependent, degrading under persona-centric abstraction [+W]

Related Strategies¶

Examples¶

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Key Sources¶

• Yongli Xiang, Zhifang Zhang, Bojun Yang, Ziming Hong, Lei Feng, Miao Xu, Tongliang Liu. (2026). When Agents Learn to Be You: Benchmarking Privacy Leakage, Impersonation Risk, and Defenses in Persona Skills. arXiv. https://arxiv.org/abs/2608.03700