Projects

My research covers three areas: AI security and safety, making AI systems themselves trustworthy; AI for cybersecurity and online safety, using AI to protect people and platforms from online harms; and human-centered security, studying how people experience and perceive online risks. Selected papers from each area are summarized below; see Publications for the full list.

AI Security and Safety

Defending LLMs against jailbreak attacks and measuring the robustness of multimodal models.

JBShield

USENIX Security 2025

JBShield framework figure showing jailbreak detection and mitigation.

JBShield defends aligned LLMs against jailbreak attacks by looking inside the model instead of filtering prompts. It identifies toxic and jailbreak-related concepts in hidden activations, then intervenes on those concepts to keep the model refusing harmful requests. Concept-aware intervention substantially reduces successful jailbreaks across diverse LLMs.

Multimodal Robustness

SKM 2023

Figure from the Multimodal Robustness paper on robustness of vision-language multimodal models.

This paper measures how robust vision-language multimodal models are when their inputs or assumptions shift, identifying where cross-modal systems become brittle before they are used in security-sensitive settings. It laid the groundwork for my later work on multimodal moderation.

AI for Cybersecurity and Online Safety

Using LLMs, multimodal LLMs, and vision-language models to detect hateful videos, harmful memes, illicit game promotion, and hate speech.

HVGuard

EMNLP 2025

HVGuard framework figure showing multimodal reasoning and mixture-of-experts fusion.

HVGuard detects hateful videos, where harm is often carried jointly by speech, visuals, sarcasm, and pacing. It feeds transcripts and video frames to a multimodal LLM pipeline that reasons over evidence across modalities, improving detection of implicit, context-dependent hate in short videos.

HMGuard

NDSS 2025

HMGuard overview figure showing challenge identification, prompt design, and harmful meme detection.

HMGuard detects harmful memes, where a small amount of text and imagery can carry hateful, harassing, or propagandistic intent. It uses multimodal LLMs to reason about how the image, the overlaid text, and their cultural references combine, treating moderation as a meme-understanding task.

UGCG-Guard

USENIX Security 2024

UGCG-Guard overview figure showing data collection, prompting, VLM detection, and moderation.

UGCG-Guard detects illicit promotion that lures users, especially minors, into unsafe user-generated content games. It uses large vision-language models to screen social posts, screenshots, and game imagery for sexualized or exploitative content, despite platform-specific slang and fast-changing promotion styles.

NewWave

IEEE S&P 2024

HateGuard overview figure from the NewWave paper.

NewWave moderates hate speech that surges around breaking events, when static policies and existing classifiers go stale. It uses chain-of-thought reasoning in LLMs to capture the narratives, slogans, and references tied to each new wave, so detection can adapt without retraining a model for every shift.

LLM4HateSpeech

ICMLA 2023

Prompting strategy and results figure from the LLM4HateSpeech paper.

LLM4HateSpeech evaluates whether LLMs can detect hate speech in realistic, context-heavy settings. It compares prompting strategies and measures how context, task framing, and external knowledge affect LLM judgments on subtle or ambiguous hateful language, showing where LLMs help and where they remain brittle.

Human-centered Security

Studying how people, especially children and their parents, perceive and experience risk in online spaces.

Beyond Age-Based Restrictions

CHI 2026

Key risk-distribution figure from the RethinkingUGCG paper.

This study compares how parents and children perceive risk in user-generated content games, and finds a gap between adult oversight and what children actually encounter in these games. It argues for context-aware safety interventions beyond blanket age-based restrictions.