Problem Summary

In cloud storage services, privacy risks are heightened due to the interconnected nature of user data and shared files. Third-party applications often request full access to users' files, including those shared with collaborators, leading to significant privacy risks for all parties involved.

Rationale

To mitigate privacy risks in cloud environments, it is crucial to develop mechanisms that account for interdependent privacy concerns, informing users about the privacy decisions of their collaborators and encouraging privacy-preserving behaviours.

Solution

Develop systems that provide users with information about previously authorised vendors, promote History-based decisions to minimise privacy loss, and include privacy indicators to encourage compliance with privacy-preserving practices.

Harkous and Aberer [1] addressed interdependent privacy in cloud applications by introducing mechanisms that consider the privacy implications of collaborators' actions on shared data. In cloud services like Google Drive and Dropbox, when one user authorises a third-party app, it often gains access not only to their files but also to files shared by other collaborators. This interconnected nature of data access creates privacy risks for all parties involved.
To mitigate these risks, the authors propose History-based decisions, which inform users about previously authorised vendors. By highlighting which third-party apps have already been granted access, this mechanism encourages users to avoid installing new apps that require similar permissions, thus minimising additional privacy loss.
Moreover, the system includes a privacy indicator that provides visual cues to users about the potential privacy risks associated with new app installations. This indicator aims to enhance user awareness and guide them towards privacy-preserving decisions. Through these measures, the solution emphasises the importance of considering collaborators' privacy when making decisions about app authorisations, thereby effectively managing interdependent privacy risks in cloud environments.

Platforms: personal computers, mobile devices

Example

Proposed "History-based insights" interface as in [1]. (See enlarged)

• The study demonstrated that teams can reduce privacy loss by up to 40% by considering the decisions made by their team members. It also improved users' awareness of previously authorised vendors, helping them understand the privacy implications of their collaborators' actions [1].

• Despite demonstrating the effectiveness of History-based Insights, the authors acknowledge that their study has limitations due to its reliance on a web experiment with hypothetical data [1].

Considering the design space for privacy notices [2], this guideline can be applied to the following dimensions:

By implementing History-based decisions and privacy indicators, the guideline aims to enhance users' ability to manage and influence the privacy settings of shared content, thus addressing the core element of Control [3]. Other related privacy attributes: