P3: Toward Privacy-Preserving Photo Sharing
Moo-Ryong Ra, Ramesh Govindan, Antonio J. Ortega · arXiv (Cornell University) · 2013
With increasing use of mobile devices, photo shar-ing services are experiencing greater popularity. Aside from providing storage, photo sharing services enable bandwidth-efficient downloads to mobile devices by performing server-side image transformations (resizing, cropping). On the flip side, photo sharing services have raised privacy concerns such as leakage of photos to unauthorized viewers and the use of algorithmic recog-nition technologies by providers. To address these con-cerns, we propose a privacy-preserving photo encoding algorithm that extracts and encrypts a small, but signif-icant, component of the photo, while preserving the re-mainder in a public, standards-compatible, part. These two components can be separately stored. This technique significantly reduces the accuracy of automated detec-tion and recognition on the public part, while preserving the ability of the provider to perform server-side trans-formations to conserve download bandwidth usage. Our prototype privacy-preserving photo sharing system, P3, works with Facebook, and can be extended to other ser-vices as well. P3 requires no changes to existing services or mobile application software, and adds minimal photo storage overhead. 1