People value their privacy but often lack the time to read privacy policies. This issue is exacerbated in the context of mobile apps, given the variety of data they collect and limited screen space for disclosures. Privacy nutrition labels have been proposed to convey data practices to users succinctly, obviating the need for them to read a full privacy policy. In fall 2020, Apple introduced privacy labels for mobile apps, but research has shown that these labels are ineffective, partly due to their complexity, confusing terminology, and suboptimal in- formation structure. We propose a new design for mobile app privacy labels that addresses information layout challenges by representing data collection and use in a color-coded, expand- able grid format. We conducted a between-subjects user study with 200 Prolific participants to compare user performance when viewing our new label against the current iOS label. Our findings suggest that our design significantly improves users’ ability to answer key privacy questions and reduces the time required for them to do so.
more »
« less
This content will become publicly available on August 13, 2025
Exploring Expandable-Grid Designs to Make iOS App Privacy Labels More Usable
People value their privacy but often lack the time to read privacy policies. This issue is exacerbated in the context of mobile apps, given the variety of data they collect and limited screen space for disclosures. Privacy nutrition labels have been proposed to convey data practices to users succinctly, obviating the need for them to read a full privacy policy. In fall 2020, Apple introduced privacy labels for mobile apps, but research has shown that these labels are ineffective, partly due to their complexity, confusing terminology, and suboptimal information structure. We propose a new design for mobile app privacy labels that addresses information layout challenges by representing data collection and use in a color-coded, expandable grid format. We conducted a between-subjects user study with 200 Prolific participants to compare user performance when viewing our new label against the current iOS label. Our findings suggest that our design significantly improves users' ability to answer key privacy questions and reduces the time required for them to do so.
more »
« less
- Award ID(s):
- 2150217
- PAR ID:
- 10574916
- Publisher / Repository:
- Usenix
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Privacy labels---standardized, compact representations of data collection and data use practices---are often presented as a solution to the shortcomings of privacy policies. Apple introduced mandatory privacy labels for apps in its App Store in December 2020; Google introduced mandatory labels for Android apps in July 2022. iOS app privacy labels have been evaluated and critiqued in prior work. In this work, we evaluated Android Data Safety Labels and explored how differences between the two label designs impact user comprehension and label utility. We conducted a between-subjects, semi-structured interview study with 12 Android users and 12 iOS users. While some users found Android Data Safety Labels informative and helpful, other users found them too vague. Compared to iOS App Privacy Labels, Android users found the distinction between data collection groups more intuitive and found explicit inclusion of omitted data collection groups more salient. However, some users expressed skepticism regarding elided information about collected data type categories. Most users missed critical information due to not expanding the accordion interface, and they were surprised by collection practices excluded from Android's definitions. Our findings also revealed that Android users generally appreciated information about security practices included in the labels, and iOS users wanted that information added.more » « less
-
Abstract We present the design, implementation and evaluation of a system, called MATRIX, developed to protect the privacy of mobile device users from location inference and sensor side-channel attacks. MATRIX gives users control and visibility over location and sensor (e.g., Accelerometers and Gyroscopes) accesses by mobile apps. It implements a PrivoScope service that audits all location and sensor accesses by apps on the device and generates real-time notifications and graphs for visualizing these accesses; and a Synthetic Location service to enable users to provide obfuscated or synthetic location trajectories or sensor traces to apps they find useful, but do not trust with their private information. The services are designed to be extensible and easy for users, hiding all of the underlying complexity from them. MATRIX also implements a Location Provider component that generates realistic privacy-preserving synthetic identities and trajectories for users by incorporating traffic information using historical data from Google Maps Directions API, and accelerations using statistical information from user driving experiments. These mobility patterns are generated by modeling/solving user schedule using a randomized linear program and modeling/solving for user driving behavior using a quadratic program. We extensively evaluated MATRIX using user studies, popular location-driven apps and machine learning techniques, and demonstrate that it is portable to most Android devices globally, is reliable, has low-overhead, and generates synthetic trajectories that are difficult to differentiate from real mobility trajectories by an adversary.more » « less
-
Apple introduced privacy labels in Dec. 2020 as a way for developers to report the privacy behaviors of their apps. While Apple does not validate labels, they also require developers to provide a privacy policy, which offers an important comparison point. In this paper, we fine-tuned BERT-based language models to extract privacy policy features for 474,669 apps on the iOS App Store, comparing the output to the privacy labels. We identify discrepancies between the policies and the labels, particularly as they relate to data collected linked to users. We find that 228K apps' privacy policies may indicate data collection linked to users than what is reported in the privacy labels. More alarming, a large number (97%) of the apps with a Data Not Collected privacy label have a privacy policy indicating otherwise. We provide insights into potential sources for discrepancies, including the use of templates and confusion around Apple's definitions and requirements. These results suggest that significant work is still needed to help developers more accurately label their apps. Our system can be incorporated as a first-order check to inform developers when privacy labels are possibly misapplied.more » « less
-
Mobile applications (apps) provide users valuable benefits at the risk of exposing users to privacy harms. Improving privacy in mobile apps faces several challenges, in particular, that many apps are developed by low resourced software development teams, such as end-user programmers or in startups. In addition, privacy risks are primarily known to users, which can make it difficult for developers to prioritize privacy for sensitive data. In this paper, we introduce a novel, lightweight method that allows app developers to elicit scenarios and privacy risk scores from users directly using only an app screenshot. The technique relies on named entity recognition (NER) to identify information types in user-authored scenarios, which are then fed in real-time to a privacy risk survey that users complete. The best-performing NER model predicts information types with a weighted average precision of 0.70 and recall of 0.72, after post-processing to remove false positives. The model was trained on a labeled 300-scenario corpus, and evaluated in an end-to-end evaluation using an additional 203 scenarios yielding 2,338 user-provided privacy risk scores. Finally, we discuss how developers can use the risk scores to prioritize, select and apply privacy design strategies in the context of four user-authored scenarios.more » « less