Sharing and privacy using untrusted storage

Broadband connections to the Internet are enabling a new set of applications and services. Of interest is the impact of this additional bandwidth on current file system models. These models are being challenged as the Internet is enabling global file access, cross-domain sharing, and the use of Internet-based storage services. Various network file systems [3, 15, 8] offer ubiquitous file access, research systems [9] have offered solutions to cross-domain sharing, and cryptographic file systems [2, 5] addressed concerns regarding the trust of system administrators and data security. The Internet model requires that all these ideas be integrated into a single system. This thesis describes a new file system called bFS that addresses the challenges of this new model by eliminating the assumption that servers (specifically, their administrators) are trusted. Instead, agents sue trusted to manage data, metadata, authentication with storage providers, and enforcing access control. This enables global access and cross-domain sharing using untrusted storage servers.Science, Faculty ofComputer Science, Department ofGraduat