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Verifiable Data Registry (VDR) for Identus on Cardano

Project Catalyst – Project Completion Overview

This document summarizes the completion of the Project Catalyst initiative to design and deliver a Verifiable Data Registry (VDR) framework for Identus on Cardano.

The project resulted in a fully open-source, modular, and production-ready VDR ecosystem, including specifications, multiple implementations, and real Cardano integrations, all developed and maintained under Hyperledger Identus.

What Is the VDR?​

A Verifiable Data Registry (VDR) is a foundational component for decentralized trust systems.
It enables data to be:

  • Published in a verifiable way
  • Resolved independently by any party
  • Cryptographically verified
  • Stored across different backends (blockchain, database, files)

In Identus, VDRs are used for:

  • DID documents and operations
  • Credential schemas and definitions
  • Trust and identity metadata anchored on Cardano

This project establishes VDRs as a generic, reusable abstraction, not tied to a single implementation or storage layer.

What Was Delivered​

1. Generic VDR Specification​

A technology-agnostic specification defining:

  • VDR interfaces and responsibilities
  • Driver families and versions
  • URL-based resolution model
  • Immutable and mutable data handling
  • Cryptographic proof mechanisms

This specification allows any storage backend to implement a VDR consistently.

Links

2. Cardano / PRISM VDR Specification​

A Cardano-specific VDR protocol describing:

  • How verifiable data is anchored in Cardano transactions
  • Metadata encoding and verification rules
  • Compatibility with DID PRISM and Identus architecture

Links

3. Generic VDR Driver (Kotlin)​

A reference implementation of the generic VDR specification:

  • Implemented in Kotlin
  • Demonstrates how to build VDR drivers
  • Used for validation, testing, and non-ledger backends

Links

4. PRISM VDR Driver Implementations​

To prove real-world applicability, multiple independent PRISM VDR drivers were implemented.

Scala PRISM VDR Driver​

  • Uses the Blockfrost API
  • Supports file-based and MongoDB indexing
  • Published as reusable artifacts

Links

NeoPrism VDR Driver (Rust)​

  • Rust-based Cardano indexing and resolution service
  • Pluggable input feeds (Blockfrost, DBSync, custom)
  • REST API for VDR resolution
  • W3C-compliant DID resolution

Links

Prism-Node + Cloud-Agent Integration​

The production Identus stack:

  • prism-node performs Cardano ledger operations
  • cloud-agent exposes REST and DIDComm APIs
  • Together they provide a complete Cardano-backed VDR service

Links

Public Demonstration​

A full end-to-end demonstration was recorded and published, showing:

  • VDR architecture in practice
  • Multiple driver implementations
  • Cardano-anchored publishing and resolution flows

Final demo video (start at 06:55)
https://www.youtube.com/watch?v=K1LhBHkOREE

Why This Matters​

This Catalyst project delivered core infrastructure, not a one-off feature:

  • A reusable VDR standard for Identus
  • Multiple interoperable implementations
  • Cardano-native anchoring and resolution
  • Open governance under Hyperledger
  • A foundation for future identity and trust use cases

The VDR system is now a shared building block for decentralized trust on Cardano.

Project Status​

Status: ✅ Completed
All deliverables: Open source and publicly verifiable
Governance: Hyperledger Identus (Linux Foundation Decentralized Trust)

This document serves as community-facing evidence of completion for the full Project Catalyst initiative.