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Thesis Defense - Dunn

SafeShare: Secure File Sharing Across Trust Boundaries
Joseph Dunn
Computer Science PhD Candidate

The emergence of the Internet and associated networked applications has created a host of ways in which individual users can create and access information. At the same time, related security and social concerns have led to the creation and wide deployment of protective mechanisms that prevent malicious users from gaining unauthorized access to networked resources, particularly information. Trust domains have thus been created and define the practical boundaries of who can access what information. Computer systems and users outside a trust boundary are given minimal access, while machines and users within the boundary are allowed more freedom. The beneficial impact of such mechanisms is that important information and resources are protected. However, trust boundaries also place significant barriers to the use of these resources by legitimate users, even in common situations. For example, true file sharing (especially write sharing) is rarely supported across trust boundaries. It is in particular quite difficult to share files without sharing the ownership of those files.

This thesis describes the design, implementation and evaluation of SafeShare, a software system that facilitates file sharing across trust boundaries. SafeShare supports the creation of transitive reputation-based relationships for sharing files and other web-accessible content. These trust relationships are then used to manage the sharing of information between users. A novel aspect of SafeShare is its use of trust relationships that are modeled upon human interactions and reputation systems.

Committee: John Bennett, Professor (Co-Chair)
John Black, Assistant Professor (Co-Chair)
Douglas Sicker, Assistant Professor
Dirk Grunwald, Associate Professor
Paul Ohm, Law School
Department of Computer Science
University of Colorado Boulder
Boulder, CO 80309-0430 USA
May 5, 2012 (14:20)