Ph.D. Theses

WebSig: A Digital Signature Framework for the Web

By James McCusker
Advisor: Deborah McGuinness
September 8, 2014

WebSig is a digital signature scheme for the web that uses Resource Description Framework (RDF) graphs to express its documents, document metadata, and signature data in a way that leverages existing trustable digital signature schemes to create signatures that are both computable and trustable. We demonstrate this by showing how digital signature scheme that are attributable, verifiable, linkable, revisable, and portable, are also computable and trustable digital signature schemes. We also introduce evaluation criteria for those five qualities and demonstrate how WebSig provides all five. WebSig supports the verifiable signing of any RDF Graphs of Practical Interest (GPI) through the use of another contribution, the Functional Requirements for Information Resources (FRIR) information identity framework. FRIR is a provenance-driven identity framework that can provide interrelated identities for RDF graphs and other information resources. The FRIR Graph Digest Algorithm, a third contribution, provides an algorithm that can create platform-independent, cryptographically secure, reproducible identifiers for GPIs. FRIR and the FRIR Graph Digest Algorithm both supply the means to securely identify the signed document and any supporting RDF graphs, and are essential to supplying all five qualities needed to provide computable and trustable signatures. WebSig builds off of existing technologies and vocabularies from the domains of cryptography, computer security, semantic web services, semantic publishing, library science, and provenance.

This dissertation's contributions will be presented as follows: 1) Sufficiency proof that attributable, verifiable, portable, linkable, revisable digital signature schemes are trustable and computable; 2) Functional Requirements for Information Resources (FRIR), a provenance-enabled, trustable, computable identity framework for information resources; 3) the FRIR RDF Graph Digest Algorithm, an algorithm that provides reproducible identifiers for Graphs of Practical Interest (GPIs), a class of graphs that we formally define; and 4) WebSig, a framework that lets users create legally-binding electronic documents that are both trustable and computable.

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