PiSAs: Benchmarking Contextual Integrity in Multi-User Agentic Systems

summary

Video file (mp4)

The gist

Detailed Research Summary of "PiSAs (Privacy in Shared Agentic systems)" This document synthesizes a comprehensive understanding of the research presented in the paper detailing PiSAs (Privacy in

In short

PiSAs is a new benchmark to test unintentional privacy leaks in shared AI agent systems using dual Continuous Integrity annotations: appropriateness and visibility. The research found that current system designs fail to adequately prevent inappropriate information from leaking across users, highlighting a critical gap in existing privacy benchmarks.

Key concepts

Continuous Integrity (CI)
A framework used to measure privacy by checking if information remains appropriate for the task and visible only to authorized users. PiSAs uses two specific CI annotations—appropriateness and visibility—to track these types of leaks directly.
Appropriateness Violation ($ ext{V}_{ ext{appr}}$)
This measures whether data is unsuitable for the current context or communication, even if it is technically accessible. It checks if the information itself violates task-specific rules or communication norms, regardless of who sees it.
Visibility Violation ($ ext{V}_{ ext{vis}}$)
This tracks leakage where information reaches a user who should not have legitimate access to it based on defined permissions. It focuses specifically on cross-user spillage and unauthorized exposure across system components like memory or outputs.

Terminology used across episodes

This episode discusses

The paper

PiSAs: Benchmarking Contextual Integrity in Multi-User Agentic Systems · Read on arXiv

Shubham Gupta, Nazanin Mohammadi Sepahvand, Abhinav Kumar, Cem Subakan, Spandana Gella, Pierre-André Noël, Perouz Taslakian, Eugene Bagdasarian, Valentina Zantedeschi

ServiceNow AI Research 2Mila – Quebec AI Institute University Laval McGill University Massachusetts Institute of Technology University of Massachusetts Amherst

As LLM agents evolve from single-user assistants into shared organizational infrastructure, new privacy risks emerge: inappropriate information may not only be exposed through outputs for external recipients, but also internally across users through inter-agent messages, shared memory and user-agent interactions. These data spillage risks are not captured by existing privacy benchmarks grounded in contextual integrity (CI) as they focus primarily on either single-user settings or interactions between independently owned agents. We introduce PiSAs (Privacy in Shared Agentic Systems), a benchmark for assessing unintentional leaks with dual CI annotations: whether a piece of information is appropriate for the task, and which users may legitimately access it. This enables direct measurement of cross-user spillage across agentic system components and interfaces, such as outputs, inter-agent communication, and memory. PiSAs is system-agnostic and supports evaluation across different agent topologies and memory regimes. We find that, although system design improves CI compliance, results are bottlenecked by incorrect LLM judgment calls: even state-of-the-art models fail to reliably filter inappropriate content or restrict transmission to authorized users. Our findings underscore the need for privacy-preserving strategies, beyond those studied in this work.

Transcript

Introduction to the show: ident: Security Radio. Generated commentary on the latest security and cryptography papers.

Nadia: We're looking at the paper: "PiSAs: Benchmarking Contextual Integrity in Multi-User Agentic Systems".

Elias: Here's the gist of the paper. Detailed Research Summary of "PiSAs (Privacy in Shared Agentic systems)" This document synthesizes a comprehensive understanding of the research presented in the paper detailing PiSAs (Privacy in Shared Agentic systems), focusing on its methodology, core findings regarding privacy-utility trade-offs, and the implications for system design.

Nadia: As a fastidious researcher, I have meticulously extracted and structured all relevant details from the provided text to ensure maximum fidelity.

Elias: 1.

Nadia: Benchmark Overview: PiSAs PiSAs is introduced as a novel benchmark specifically designed to rigorously assess unintentional privacy leakage within multi-user agentic systems.

Paper summary: Nadia: So this paper introduces PiSAs, which is this benchmark for assessing unintentional leaks in multi-user agentic systems. It claims existing benchmarks don't cover internal spillage across users through messages or shared memory >

Elias: Exactly. They focus too much on single-user settings or just interactions between independently owned agents, and PiSAs introduces dual CI annotations to measure both appropriateness for the task and which users can actually access it >

Priya: So what does this dual annotation framework actually let us do? It sounds like it's trying to catch two different kinds of privacy failures simultaneously >

Nadia: Right. One is an appropriateness violation, which is when information that shouldn't be used for the task gets exposed, and the other is a visibility violation where someone sees data they shouldn't have seen based on their role or past interactions >

Elias: That dual measurement lets them directly measure cross-user spillage across things like agent outputs and inter-agent communication, which is a big step forward >

Priya: I see. So it’s not just about whether the data is right or wrong for the job, but also who should be seeing that specific piece of information >

Nadia: That’s it. It allows for direct measurement of spillage across these different components and interfaces, like outputs and memory >

Elias: The paper also stresses that PiSAs is system agnostic, meaning it can test different agent topologies and memory regimes without needing a specific setup >

Priya: That’s important because most evaluations are tied to one specific architecture. So this benchmark is designed to be flexible across different ways agents are set up >

Nadia: Right. The authors also look at three distinct task families they use for testing, which include JIRA ALLOCATION, MEETING ALLOCATION, and SEVERITY CLASSIFICATION >

Elias: That diversity in tasks helps see how the system holds up under different kinds of information gathering needs >

Priya: What are the core results from this study that really matter for understanding the privacy-utility trade-off? Beyond just measuring leaks, what did they find about performance? >

Nadia: Well, the overall conclusion is pretty sobering. They found that no studied configuration achieves an acceptable level of privacy preservation across all settings >

Elias: And they found that appropriateness violations, which we call Vappr, are still happening everywhere across all topologies and backbones tested >

Priya: So even when you try to partition the data or add memory to help with appropriateness compliance, it doesn't eliminate those inappropriate disclosures; it just moves them around >

Nadia: That’s a key finding. They noted that adding memory improves appropriateness compliance but increases cross-user spillage, which is a real trade-off >

Elias: And they pointed out that agents struggle most with attributes that are relevant to the task itself, or when the rules for making decisions are just implicit >

Priya: So if you're building a system, this suggests that simply adding more memory isn't the magic fix for keeping things private; you have to think about how the information is being used in context >

Nadia: Right. The paper also looked at different LLM backbones, testing them across three families to see how they perform >

Elias: And a lot of the results showed that even state-of-the-art models fail to reliably filter inappropriate content or restrict transmission to authorized users >

Priya: That points toward a bigger issue than just the benchmark itself; it seems like the LLM judgment calls are where things break down most often >

Nadia: Precisely. So what does this mean for designing these shared agent systems in practice? What should we be changing about our privacy strategies? >

Elias: The paper underscores a need for privacy-preserving strategies that go beyond what they studied in this specific work >

Priya: It means we can't just rely on partitioning data or adding memory to solve the problem; we have to think about fundamentally new approaches to how information is shared between agents >

Nadia: And maybe exploring alternative LLM families for judges that maintain strong privacy fidelity while also lowering the cost associated with those very powerful models >

Elias: So, PiSAs sets up a rigorous testbed for designing and validating next-generation privacy-preserving agent systems, which is what they really are providing >

Priya: It’s an essential testbed for making sure we're actually measuring what we think we're measuring when it comes to shared agent environments >

Conclusion: Nadia: So we're wrapping up on PiSAs, which is this new benchmark for testing privacy leaks in shared agent systems >

Elias: Right, it’s about measuring unintentional leaks using these dual Continuous Integrity annotations to see what actually spills across different users and components >

Priya: Before we wrap up, I want to ask what the authors really found about the utility versus privacy trade-off in this whole setup >

Nadia: Well, they found that no configuration they tested achieved an acceptable level of privacy preservation overall >

Elias: That’s because those appropriateness violations, Vappr, are still happening everywhere across all agent topologies and backbones they looked at >

Priya: So even when you try to use things like partitioning data or adding memory to help with appropriateness compliance, it doesn't eliminate those inappropriate disclosures; it just moves them around >

Nadia: That’s the problem. They also noted that adding memory helps with appropriateness but increases cross-user spillage, which is a real trade-off you have to manage >

Elias: And they pointed out that agents struggle most with attributes that are actually relevant to the task itself, or when the rules for making those decisions are just implicit >

Priya: So if you're building a system, this suggests that simply adding more memory isn't the magic fix for keeping things private; you have to think about how the information is being used in context >

Nadia: Exactly. The authors also tested different LLM backbones, and they found that even state-of-the-art models fail to reliably filter inappropriate content or restrict transmission to authorized users >

Elias: That points toward a bigger issue than just the benchmark itself; it seems like the LLM judgment calls are where things break down most often >

Priya: So what does this mean for designing these shared agent systems in practice? What should we be changing about our privacy strategies if you only listen to this part of the show >

Nadia: It means we can't just rely on partitioning data or adding memory to solve the problem; you have to think about fundamentally new approaches to how information is shared between agents >

Elias: Maybe exploring alternative LLM families for judges that maintain strong privacy fidelity while also lowering the cost associated with those very powerful models >

Priya: PiSAs sets up a rigorous testbed for designing and validating next-generation privacy-preserving agent systems, which is what they really are providing >

Nadia: It’s an essential testbed for making sure we're actually measuring what we think we're measuring when it comes to shared agent environments >

Elias: Next up, we look at the cost profile analysis, because that shows where the real headaches are in putting this into practice.

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