Privacy Preserving Profiling for Mobile Services

The many sensors embedded in phones nowadays provide advanced sensing capabilities that make it possible to capture real-time information about the user and his surroundings. There are already examples of apps that use this information to provide highly useful and contextual services to the users. However, users are still reluctant to share their personal data with service providers due to their privacy implications (if misused).In this work, we provide protocols that allow users to store their sensor data on third party (untrusted) cloud servers. The data is stored in encrypted form (so protected from the cloud providers) with access only to service providers explicitly pre-approved by the users. The protocols simultaneously also ensure that the data accessed by service providers is in fact ‘current’ and consistent. This is achieved by integrating transactional and cryptographic primitives, such as atomic uploads, optimistic concurrency control, proxy re-encryption and homomorphic encryption, among others. Finally, experimental results are given to illustrate the practical feasibility and scalability of the proposed protocols.