Abstract. In this paper, we present the design of gVault, a cryptographic 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 access: 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 management 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 secu...