PrivacyBench: A Conversational Benchmark for Evaluating Privacy in Personalized AI
Srija Mukhopadhyay, Sathwik Reddy, Shruthi Muthukumar, Jisun An, Ponnurangam Kumaraguru
TL;DR
PrivacyBench provides a privacy-centric benchmark to audit contextual privacy in personalized AI by embedding ground-truth secrets within evolving social contexts and evaluating multi-turn interactions. The framework combines a synthetic data-generation pipeline with direct and indirect conversational probes and a standardized set of leakage, over-secrecy, retrieval, and persona-consistency metrics, evaluated via automated judges and human checks. Empirical results reveal substantial baseline leakage in RAG-based systems, with leakage reduced by privacy-aware prompts but not eliminated, and a persistent high Inappropriate Retrieval Rate at the retrieval layer. The work highlights architectural gaps and argues for privacy-by-design safeguards, offering a foundational benchmark and methodology for building trustworthy, socially aware personalized agents.
Abstract
Personalized AI agents rely on access to a user's digital footprint, which often includes sensitive data from private emails, chats and purchase histories. Yet this access creates a fundamental societal and privacy risk: systems lacking social-context awareness can unintentionally expose user secrets, threatening digital well-being. We introduce PrivacyBench, a benchmark with socially grounded datasets containing embedded secrets and a multi-turn conversational evaluation to measure secret preservation. Testing Retrieval-Augmented Generation (RAG) assistants reveals that they leak secrets in up to 26.56% of interactions. A privacy-aware prompt lowers leakage to 5.12%, yet this measure offers only partial mitigation. The retrieval mechanism continues to access sensitive data indiscriminately, which shifts the entire burden of privacy preservation onto the generator. This creates a single point of failure, rendering current architectures unsafe for wide-scale deployment. Our findings underscore the urgent need for structural, privacy-by-design safeguards to ensure an ethical and inclusive web for everyone.
