[Paper Review] Design Patterns for Blockchain-based Self-Sovereign Identity

Yue Liu, Qinghua Lu+2 more|arXiv (Cornell University)|May 25, 2020

Blockchain Technology Applications and Security22 references4 citations

TL;DR

This paper proposes 12 design patterns for building blockchain-based self-sovereign identity systems, categorised by the lifecycle of three core objects: keys, decentralised identifiers (DIDs), and credentials. The patterns address key challenges in security, scalability, and privacy by leveraging off-chain storage with blockchain anchoring, enabling cost-effective, scalable, and privacy-preserving identity management without intermediaries.

ABSTRACT

Self-sovereign identity is a new identity management paradigm that allows entities to really have the ownership of their identity data and control their use without involving any intermediary. Blockchain is an enabling technology for building self-sovereign identity systems by providing a neutral and trustable storage and computing infrastructure and can be viewed as a component of the systems. Both blockchain and self-sovereign identity are emerging technologies which could present a steep learning curve for architects. We collect and propose 12 design patterns for blockchain-based self-sovereign identity systems to help the architects understand and easily apply the concepts in system design. Based on the lifecycles of three main objects involved in self-sovereign identity, we categorise the patterns into three groups: key management patterns, decentralised identifier management patterns, and credential design patterns. The proposed patterns provide a systematic and holistic guide for architects to design the architecture of blockchain-based self-sovereign identity systems.

Motivation & Objective

• To address the steep learning curve and lack of architectural guidance for developers building blockchain-based self-sovereign identity systems.
• To provide a systematic, holistic framework for designing secure and scalable self-sovereign identity systems using blockchain as a trustless infrastructure.
• To categorise design patterns around the lifecycles of three core identity objects: keys, decentralised identifiers (DIDs), and credentials.
• To reduce reliance on centralised intermediaries while preserving data integrity, privacy, and verifiability in identity management.
• To bridge the gap between emerging blockchain technology and practical system design through reusable, pattern-based solutions.

Proposed method

• The authors analyse the lifecycles of three core identity objects—keys, decentralised identifiers (DIDs), and credentials—to derive design patterns.
• Patterns are grouped into three categories: key management, DID management, and credential design, each aligned with state transitions in the lifecycle of the respective object.
• The Blockchain Anchor pattern is proposed to reduce on-chain costs and improve scalability by storing only hash values of off-chain data on the blockchain.
• Techniques such as selective content generation, off-chain storage, and low contract footprint patterns are integrated to preserve privacy and reduce transaction load.
• The design patterns are validated through known implementations in systems like uPort, Hyperledger Indy, Blockstack, Chainpoint, and Laava.
• The approach uses cryptographic hashing and blockchain immutability to ensure data integrity while maintaining confidentiality through off-chain data storage.

Experimental results

Research questions

• RQ1 How can system architects effectively design scalable and secure blockchain-based self-sovereign identity systems given the complexity of emerging technologies?
• RQ2 What are the key lifecycle phases of keys, decentralised identifiers, and credentials in self-sovereign identity, and how can patterns be derived from these phases?
• RQ3 How can blockchain be used efficiently to ensure data integrity without incurring high costs or sacrificing performance?
• RQ4 What mechanisms can preserve privacy while maintaining verifiability and auditability in decentralised identity systems?
• RQ5 How can off-chain data be anchored to the blockchain in a way that ensures trustworthiness and reduces on-chain overhead?

Key findings

• The paper successfully identifies and formalises 12 design patterns grouped into three categories: key management, decentralised identifier management, and credential design, each aligned with lifecycle transitions of core identity objects.
• The Blockchain Anchor pattern enables cost-effective and scalable storage by anchoring only hash values of off-chain data to the blockchain, reducing transaction volume and storage costs.
• Systems like Blockstack, Chainpoint, and Laava demonstrate the practical viability of the proposed patterns in real-world multitenant and privacy-preserving blockchain identity platforms.
• The use of cryptographic hashing ensures data integrity and immutability, while off-chain storage preserves privacy and enhances performance.
• The pattern-based approach significantly reduces architectural complexity and provides a reusable framework for developers and architects in self-sovereign identity development.
• The patterns collectively address critical challenges in self-sovereign identity, including trustlessness, decentralisation, data ownership, and verifiability, without relying on central intermediaries.