Technical Report: The Need for a (Research) Sandstorm through the Privacy Sandbox

2025-12-02

AI Summary

The Google Privacy Sandbox aims to curb cross-site and cross-app tracking, yet its APIs may fundamentally reshape digital advertising, mobile, and web ecosystems. This paper introduces a systematic research framework that integrates literature review, technical reverse engineering, empirical measurement, and open collaboration to rigorously assess the Privacy Sandbox’s real-world impacts on user privacy, security, usability, and utility. As a key contribution, we develop “Privacy Sandstorm”—an open-source research portal that unifies diverse tools, datasets, and findings, delivering more transparent and verifiable technical insights than official documentation. Our publicly released resources significantly broaden and deepen scholarly understanding of the Privacy Sandbox’s ecosystem-wide implications, providing empirically grounded evidence to inform policy development and technical standardization. (136 words)

Technology Category

• Application Domains: Security
• Machine Learning: Privacy
• Search and Optimization: Applications

Application Category

• Security and Privacy: Large-scale security measurements
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization

Abstract

The Privacy Sandbox, launched in 2019, is a series of proposals from Google to reduce ``cross-site and cross-app tracking while helping to keep online content and services free for all''. Over the years, Google implemented, experimented, and deprecated some of these APIs into their own products (Chrome, Android, etc.) which raised concerns about the potential of these mechanisms to fundamentally disrupt the advertising, mobile, and web ecosystems. As a result, it is paramount for researchers to understand the consequences that these new technologies, and future ones, will have on billions of users if and when deployed. In this report, we outline our call for privacy, security, usability, and utility evaluations of these APIs, our efforts materialized through the creation and operation of Privacy Sandstorm (https://privacysandstorm.github.io); a research portal to systematically gather resources (overview, analyses, artifacts, etc.) about such proposals. We find that our inventory provides a better visibility and broader perspective on the research findings in that space than what Google lets show through official channels.

Problem

• Evaluating Privacy Sandbox APIs' impact on ecosystems
• Assessing privacy, security, usability, and utility concerns
• Systematically gathering resources for independent research analysis

Innovation

• Creates research portal for systematic API evaluation
• Gathers resources to assess privacy and security impacts
• Provides broader perspective than official Google channels