Compact and Selective Disclosure for Verifiable Credentials

2025-05-30

AI Summary

To address the excessive size and network overhead of verifiable credentials (VCs) during selective disclosure in self-sovereign identity (SSI) systems—particularly hindering deployment on resource-constrained devices—this paper proposes CSD-JWT, the first compact, selectively disclosable JWT scheme leveraging cryptographic accumulators for VC claim encoding. We design a zero-knowledge–friendly claim encoding and verification protocol, and extend the JWT standard to natively support accumulator-based proofs, thereby compressing both VC storage and verifiable presentation (VP) generation. Experiments demonstrate up to 46% reduction in VC storage overhead and 27–93% VP size reduction, significantly enhancing feasibility for edge devices such as hardware wallets. Our core innovation lies in integrating cryptographic accumulators into structured VC encoding—achieving minimal representation and efficient verification while preserving integrity and privacy.

Technology Category

• Application Domains: Humanities & Computational Social Science
• Data Mining & Knowledge Management: Data Compression
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories

Application Category

• Security and Privacy: Data transparency and provenance
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT

Abstract

Self-Sovereign Identity (SSI) is a novel identity model that empowers individuals with full control over their data, enabling them to choose what information to disclose, with whom, and when. This paradigm is rapidly gaining traction worldwide, supported by numerous initiatives such as the European Digital Identity (EUDI) Regulation or Singapore's National Digital Identity (NDI). For instance, by 2026, the EUDI Regulation will enable all European citizens to seamlessly access services across Europe using Verifiable Credentials (VCs). A key feature of SSI is the ability to selectively disclose only specific claims within a credential, enhancing privacy protection of the identity owner. This paper proposes a novel mechanism designed to achieve Compact and Selective Disclosure for VCs (CSD-JWT). Our method leverages a cryptographic accumulator to encode claims within a credential to a unique, compact representation. We implemented CSD-JWT as an open-source solution and extensively evaluated its performance under various conditions. CSD-JWT provides significant memory savings, reducing usage by up to 46% compared to the state-of-the-art. It also minimizes network overhead by producing remarkably smaller Verifiable Presentations (VPs), reduced in size by 27% to 93%. Such features make CSD-JWT especially well-suited for resource-constrained devices, including hardware wallets designed for managing credentials.

Problem

• Enabling selective disclosure in Verifiable Credentials for privacy
• Reducing memory usage and network overhead in credential management
• Optimizing Verifiable Presentations for resource-constrained devices

Innovation

• Uses cryptographic accumulator for compact encoding
• Reduces memory usage by up to 46%
• Minimizes network overhead with smaller VPs