Login System for OpenID Connect with Verifiable Credentials

This research paper addresses the challenges and solutions in adopting Self-Sovereign Identity (SSI) as a modern paradigm for managing digital identities. We introduce a straight-forward yet effective system that integrates SSI-based sign-ins with existing services through widely accepted protocols such as OpenID Connect and OAuth 2.0. This system is designed to bridge the gap between traditional identity management frameworks and the emerging SSI approach, offering enhanced user control over personal information through highly configurable claim handling and cross-device authentication flows, particularly using a smartphone identity wallet. We specifically explore the addition of an SSI Verifier to Authorization Servers and Identity Providers, utilizing the OpenID Connect for Verifiable Presentations (OIDC4VP) standard. This enables platforms such as Keycloak to accept SSI credentials compliant with W3C standards, allowing seamless user authentication across various applications. The proposed system is not only designed to simplify the adoption for developers by relying solely on open standards, including the recent OpenID for Verifiable Credentials, but is also shared as open-source software to serve as both a prototype and a reference implementation. Our technical discussion outlines the specific sign-in flows, demonstrating the practical feasibility and benefits of integrating SSI into existing digital environments. By ensuring privacy and ease of integration, this paper advances the broader adoption of SSI, paving the way for future innovations in digital identity management.