A Privacy-Preserving Method for Photo Sharing in Instant Message Systems

In instant messaging systems, photos have become an expressive form of real-time content sharing among users. Unfortunately, faces of stakeholders, who are depicted in the shared photos, may be exposed to unexpected viewers. This may lead to privacy leakages. In this paper, an approach is proposed to prevent such leakages, which is based on access control and face recognition. Each time a photo is sent, all stakeholders are recognized, and their faces are hidden from viewers. At the same time, stakeholders will be notified about the photo, and can decide to reveal their own faces to some proper viewers later. On the other hand, similar photos are exploited to automate this revealing process when possible, so as to reduce the impact of access control on user experiences. Besides, a proof-of-concept system is constructed and its performance is evaluated. The results indicate that this approach can be applied in instant messaging systems without too much overhead.