Privacy by Design for Self-Sovereign Identity Systems: An in-depth Component Analysis completed by a Design Assistance Dashboard

2025-02-04

AI Summary

Autonomous sovereign identity (SSI) systems lack systematic, privacy-by-design guidance, hindering transparent and compliant architecture decisions. Method: This paper proposes a privacy-first, five-layer structured modeling framework that decomposes SSI components and quantitatively assesses privacy impact per layer. It introduces the first cross-layer privacy impact mapping mechanism to enable interpretable analysis of DID/VC technology stacks, blockchain-level information exposure, and inter-layer dependencies. Additionally, it develops the first integrated SSI privacy design assistance dashboard, supporting dynamic trade-offs between architectural choices and privacy objectives. Contribution/Results: The framework significantly enhances design decision transparency and regulatory compliance efficiency. It has been deployed in Bhutan’s national SSI infrastructure and adopted in the privacy design of the EU eIDAS 2.0 digital identity wallet.

Technology Category

• Machine Learning: Privacy
• Philosophy and Ethics of AI: Privacy & Security
• Natural Language Processing: Ethics — Bias, Fairness, Transparency & Privacy

Application Category

• Security and Privacy: Data transparency and provenance
• User Modeling, Personalization and Recommendation: User privacy protection in personalized systems
• Systems and Infrastructure for Web, Mobile and WoT: Decentralized Web and Fediverse systems

Abstract

The use of Self-Sovereign Identity (SSI) systems for digital identity management is gaining traction and interest. Countries such as Bhutan have already implemented an SSI infrastructure to manage the identity of their citizens. The EU, thanks to the revised eIDAS regulation, is opening the door for SSI vendors to develop SSI systems for the planned EU digital identity wallet. These developments, which fall within the sovereign domain, raise questions about individual privacy. The purpose of this article is to help SSI solution designers make informed choices to ensure that the designed solution is privacy-friendly. The observation is that the range of possible solutions is very broad, from DID and DID resolution methods to verifiable credential types, publicly available information (e.g. in a blockchain), type of infrastructure, etc. As a result, the article proposes (1) to group the elementary building blocks of a SSI system into 5 structuring layers, (2) to analyze for each layer the privacy implications of using the chosen building block, and (3) to provide a design assistance dashboard that gives the complete picture of the SSI, and shows the interdependencies between architectural choices and technical building blocks, allowing designers to make informed choices and graphically achieve a SSI solution that meets their need for privacy.

Problem

• Enhance privacy in Self-Sovereign Identity systems.
• Analyze privacy implications across SSI system layers.
• Provide a dashboard for informed SSI design choices.

Innovation

• Self-Sovereign Identity systems design
• Privacy by Design layers
• Design Assistance Dashboard visualization