Anonymous Verifiable Credentials Eliminate Tracking While Preserving Digital Identity Verification → Research

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Briefing

Traditional digital identity systems, including Verifiable Credentials (VCs) with Decentralized Identifiers (DIDs), enable pervasive digital surveillance and cross-service user tracking due to persistent personal identifiers. The Anonymous Verifiable Credentials (AVC) framework proposes a novel mechanism that combines VCs with User-issued Unlinkable Single Sign-On (U2SSO), binding credentials to service-specific pseudonyms. This new theory fundamentally redefines privacy in digital identity, offering a path towards surveillance-resistant digital interactions that empower users with control over their data while meeting stringent institutional verification requirements.

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Context

While Verifiable Credentials (VCs) offered selective disclosure and user control, their reliance on persistent personal identifiers (PIDs), often Decentralized Identifiers (DIDs), created a fundamental privacy vulnerability. This allowed service providers, or even colluding entities, to link user interactions across multiple services, undermining the very privacy benefits VCs aimed to provide and leading to comprehensive behavioral profiling.

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Analysis

The Anonymous Verifiable Credentials (AVC) framework constitutes a novel integration of existing mechanisms → Verifiable Credentials (VCs) and User-issued Unlinkable Single Sign-On (U2SSO). Users establish a master identity with an Identity Registry. For each service interaction, a unique, service-specific pseudonym is cryptographically derived from this master identity. Verifiable Credentials are then bound to these pseudonyms.

When a user presents a credential, they also provide a zero-knowledge proof of legitimate membership in an anonymity set, without revealing their specific master identity. Previous VC systems bound credentials to persistent identifiers, which enabled cross-service tracking. AVC’s core distinction lies in binding credentials to ephemeral, service-specific pseudonyms, ensuring unlinkability across different service providers, even in scenarios of collusion.

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Parameters

Core Concept → Anonymous Verifiable Credentials (AVC) Framework
New System/Protocol → Anonymous Verifiable Credentials (AVC)
Key Authors → Cirkovic Marko, Barbaraci Mariarosaria, Alupotha Jayamine, Cachin Christian
Related Protocol → User-issued Unlinkable Single Sign-On (U2SSO)
Implementation Context → Swiss Electronic Provisional Driving License Program (eLFA)

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Outlook

The AVC framework, demonstrated in the Swiss eLFA program, paves the way for widespread adoption of privacy-preserving digital identity across various sectors. In 3-5 years, this could unlock truly private online interactions for finance, healthcare, and government services, where individuals can prove necessary attributes without fear of persistent tracking or profiling. It opens avenues for further research into optimizing the computational efficiency of pseudonym derivation and proof generation for resource-constrained devices, as well as exploring its integration with other privacy-enhancing technologies.

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Verdict

This research fundamentally redefines the balance between digital identity verification and user privacy, establishing a new paradigm for surveillance-resistant decentralized identity systems.

Signal Acquired from → unibe.ch