gVault: A Gmail Based Cryptographic Network File System Ravi Chandra Jammalamadaka 1 , Roberto Gamboni 3 , Sharad Mehrotra 1 , Kent E. Seamons 2 , and Nalini Venkatasubramanian 1 1 University of California, Irvine 2 Brigham Young University 3 University of Bologna, Italy {rjammala, sharad, nalini}@ics.uci.edu, seamons@cs.byu.edu, roberto.gamboni@studio.unibo.it Abstract. In this paper, we present the design of gVault, a crypto- graphic network file system that utilizes the data storage provided by Gmail’s web-based email service. Such a file system effectively provides users with an easily accessible free network drive on the Internet. gVault provides numerous benefits to the users, including: a) Secure remote ac- cess: Users can access their data securely from any machine connected to the Internet; b) Availability: The data is available 24/7; and c) Storage capacity: Gmail provides a large amount of storage space to each user. In this paper, we address the challenges in design and implementation of gVault. gVault is fundamentally designed keeping an average user in mind. We introduce a novel encrypted storage model and key manage- ment techniques that ensure data confidentiality and integrity. An initial prototype of gVault is implemented to evaluate the feasibility of such a system. Our experiments indicate that the additional cost of security is negligible in comparison to the cost of data transfer. 1 Introduction Network file systems have become quite popular in the past two decades. In such systems, user data in the form of files is stored at a remote server. The server is then in charge of providing services such as backup, recovery, storage, access, etc, thereby absolving the user from it’s responsibility. The user can then mount the remote file system as a local drive and proceed to perform all the required file operations on the remote data. The biggest advantages of network file systems is that they allow users to remote access their data. A nomadic user can connect to the remote server from any machine connected to the Internet and access his information. A related trend is the rise in popularity of web based email service providers (WESPs). Such services provide the users with the facility to send/receive emails free of charge. The business model is typically based on advertisements that are displayed on webpages the user is currently accessing. A big advantage of such systems, like network file systems, is that they allow the user to access his email S. Barker, G.-J. Ahn (Eds.): Data and Applications Security 2007, LNCS 4602, pp. 161–176, 2007. c  IFIP International Federation for Information Processing 2007