Bachelor's Thesis Evan Christopher

How to Wisely Identify Natural Subjects in Verifiable Credentials

Abstract

Self-Sovereign Identity is an emerging concept that is gaining traction in various domains, including e-governance, healthcare, and IoT. It is the next step in the evolution of identity management, a core building block of a lot of applications and software, enabling users to prove claims made about themselves or by others without having to rely on a centralized third party. The goal of SSI is ultimately to give control over one's identity back to the hands of the users, who are natural persons or subjects.

As the adoption of SSI increases and becomes a standard among identity management practices, credentials in ecosystems of different domains will contain more sensitive information and authoritative claims. Thus, the importance of making sure that the credential subject is, indeed, who they say they are, as well as the accuracy of the subject's claims, becomes more prevalent than ever, especially considering recent trends in artificial intelligence.
However, the lack of prevailing standards and solutions in the SSI space for this identification challenge poses significant obstacles to the adoption of the concept.

This thesis presents a comparative survey of existing standards and solutions for addressing the identification challenge in SSI, drawing from both white literature and grey literature. We construct a taxonomy of such approaches and examine how identity validation is accomplished by these approaches, providing a qualitative discussion and recommendations based on the newest standards and regulations.
Subsequently, we propose a design of an approach based on our findings on the limitations of previous approaches, considered in the context of the GX Credentials project, which is part of the broader Gaia-X initiative. Gaia-X aims to create the next generation of data infrastructure for Europe, its states, its companies, and its citizens with special regard for data sovereignty.

This thesis aims to contribute to the ongoing development of SSI by offering insights into existing approaches and their applicability in real-world scenarios, as well as identifying the gaps and challenges associated with updating information in SSI ecosystems.
The findings of this research have implications for enhancing the usability and practicality of SSI systems from various aspects, ultimately contributing to the advancement of digital identity management in the context of SSI.

Research Questions

How do we link Verifiable Credentials in an SSI ecosystem to a natural person?

1. What are the existing solutions and proposals for including identifying information in Verifiable Credentials?
2. How can updates to identifying information be handled in VCs?
3. How can we engineer effective identity credentials within the GX-Credentials project?