Regaining Control over Cloud and Mobile Data

Ph.D. Thesis, University of Washington


While emerging computing technologies – such as cloud computing and small, powerful, mobile devices – offer previously unimaginable global access to data and applications, they also threaten users’ sense of control over data ownership, distribution, and properties. For example, uploading some data to a Web service – such as a document to Google Docs, a photo to Facebook, or an email to Hotmail – causes the user to lose control over that data. The user cannot ensure that the service deletes all copies of her data when she asks it to do so, that her data is not shared with advertisers, or that her data is replicated sufficiently to ensure its long-term availability. Similarly, storing data on a mobile device causes the user to lose control over that data when the device is stolen or lost; the user cannot ensure that the data can never be compromised and she cannot tell whether it has been compromised.

This dissertation examines the broad data security, privacy, and management challenges raised by modern technology and proposes a set of techniques that address these issues. We present four systems, each aiming to re-empower users with a specific aspect of their lost data control. Keypad offers remote access control and auditability for data stored on a stolen device. Vanish provides control over the lifetime of data stored in untrusted clouds. Comet lets clients customize the functionality of trusted cloud storage, while Menagerie provides a uniform view of a user’s scattered Web data. We present the design, implementation, and detailed evaluation for each of the four systems, demonstrating the feasibility of our approaches.



Columbia University Department of Computer Science