Problem Statement

The rapid evolution of digital identity systems has created a pressing need for secure, interoperable, and scalable frameworks to handle Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs). While existing OpenWallet Foundation tools address core identity management tasks—such as wallet creation, credential storage, and identity verification—there remains a gap in addressing the dynamic nature of credential sharing, cross-platform communication, and privacy-preserving features in decentralized ecosystems. Furthermore, emerging regulatory frameworks, such as the European Union Digital Identity (EUDI) Wallet, demand seamless, secure, and privacy-respecting credential management that current solutions are not fully equipped to handle.

Solution Design

We propose the Decentralized Privacy-Preserving Credential Sharing Framework (DP2CSF), a modular, flexible solution designed to fill the gaps in existing identity management systems within the OpenWallet Foundation ecosystem. This framework will focus on privacy-preserving credential exchanges, secure messaging, credential revocation, and multi-wallet interoperability. By integrating Zero-Knowledge Proofs (ZKPs), DIDComm, and scalable messaging protocols, the framework will enable seamless cross-wallet communication while ensuring GDPR compliance and alignment with the European Union's Digital Identity (EUDI) wallet standards.

Key Features

1. Privacy-Preserving Credential Sharing:
   • Leverages cryptographic techniques like Zero-Knowledge Proofs (ZKPs), enabling users to prove aspects of their identity (e.g., age, qualifications) without revealing unnecessary personal data. This minimizes data exposure and aligns with privacy-focused policies like GDPR.
2. Cross-Wallet Interoperability:
   • Supports a multi-wallet architecture, enabling users to store and manage credentials across multiple wallets, ensuring seamless integration with diverse decentralized identity ecosystems.
3. Dynamic Credential Revocation & Updates:
   • Implements a secure credential revocation mechanism, allowing credentials to be invalidated or updated without disrupting the broader decentralized ecosystem, improving security and trust.
4. Scalable and Flexible Messaging Protocols:
   • Utilizes DIDComm, a secure communication protocol for exchanging sensitive data over the decentralized web, ensuring messages remain confidential, verifiable, and tamper-proof.
5. Standardized API Layer:
   • Exposes a well-documented RESTful API, simplifying integration with decentralized applications (dApps). The API will support credential issuance, verification, sharing, revocation, and messaging, following W3C and OpenID standards.

Technical Architecture

1. Layer 1: Privacy Layer (ZKP & Encryption)
   • Zero-Knowledge Proofs (ZKPs) will allow users to share credentials while keeping sensitive data confidential.
   • Advanced encryption standards will secure credential data both at rest and during transmission.
2. Layer 2: Interoperability Layer (DIDComm & Multi-Wallet Support)
   • Integration of DIDComm to support secure, verifiable communication across decentralized identity agents.
   • Multi-wallet support enables users to seamlessly manage and share credentials from different providers.
3. Layer 3: Credential Revocation and Lifecycle Management
   • Implement credential revocation via Revocation Registries, ensuring old or invalid credentials cannot be misused.
   • Lifecycle management tools will help manage the validity period of credentials, ensuring timely updates.
4. Layer 4: API Layer
   • Exposes a RESTful API for developers to interact with the system, managing credential issuance, verification, sharing, and revocation, while maintaining compliance with OpenWallet protocols and standards.

Implementation Plan

1. Phase 1: Design & Architecture
   • Finalize the technical architecture and framework design.
   • Define APIs, data models, and protocols.
   • Establish user and developer documentation for the framework.
2. Phase 2: Initial Development
   • Develop core components: ZKP-based privacy layer, DIDComm integration, and multi-wallet support.
   • Set up test environments and initiate unit testing.
   • Begin drafting the first set of API calls and endpoints.
3. Phase 3: Integration & Testing
   • Test compatibility with existing OpenWallet tools.
   • Ensure privacy-preserving features and cross-wallet interoperability.
   • Conduct security audits and implement improvements based on findings.