Zero-Knowledge Tenant Credentials using Veridian DID/VC

[Proposal setup] Proposal title

Please provide your proposal title

Zero-Knowledge Tenant Credentials using Veridian DID/VC

[Proposal Summary] Budget Information

Enter the amount of funding you are requesting in ADA

75000

[Proposal Summary] Time

Please specify how many months you expect your project to last

6

[Proposal Summary] Translation Information

Please indicate if your proposal has been auto-translated

No

Original Language

en

[Proposal Summary] Problem Statement

What is the problem you want to solve?

Tenants must reveal sensitive documents to prove eligibility (income, age), creating privacy risks and inefficiency. No privacy-preserving verification exists today.

[Proposal Summary] Supporting Documentation

Supporting links

• https://cardanofoundation.org/blog/veridian-digital-identity-platform
,
• https://www.keyholder.ie/

[Proposal Summary] Project Dependencies

Does your project have any dependencies on other organizations, technical or otherwise?

No

Describe any dependencies or write 'No dependencies'

Platform & Standards: Veridian wallet/SDK with KERI DIDs and ACDC credentials; Cardano (testnet/mainnet) for DID anchoring, schema hashes, and revocation/status lookups; ZK libraries (Bulletproofs via WASM or Circom/SnarkJS) integrated into mobile. Partners: Pilot host (Irish housing authority/AHB), at least one ID/KYC issuer and one income issuer (bank/employer). Cardano Foundation’s Veridian team for alignment/support. Data/Policy: Access to current eligibility rules (income thresholds/age), acceptance of ZK proofs as valid evidence during the pilot. Assumptions: Veridian sandbox access; ability to register issuer DIDs/schemas on Cardano; small pilot cohort (20–30 users) with consent. Mitigations: If issuers are slow, Blockia acts as interim issuer for pilot; if mobile proving is slow, add optional assisted proving (no raw data leaves device); if policy acceptance lags, run ZK in parallel with today’s document checks.

[Proposal Summary] Project Open Source

Will your project's outputs be fully open source?

Yes

License and Additional Information

Yes. All components will be open-sourced under MIT. The ZK circuits, wallet integrations, and verifier app will be published on GitHub for reuse by the Cardano community. veridian wallet and framework are already Open Source - MIT licensed.

[Theme Selection] Theme

Please choose the most relevant theme and tag related to the outcomes of your proposal.

Privacy

[Campaign Category] Category Questions

Describe what makes your idea innovative compared to what has been previously funded (whether by you or others).

We combine SSI (KERI/ACDC) with zero-knowledge range proofs on Cardano so tenants prove “income ≤ X / age ≥ Y” without revealing values. Credentials embed Pedersen commitments once, then support many predicates (“issue once, prove many”). This privacy-by-design, predicate-agnostic model, open-sourced as a Veridian ZK module, goes beyond prior funded work that shared raw attributes or required issuer involvement per policy.

Describe what your prototype or MVP will demonstrate, and where it can be accessed.

A Veridian wallet build with a ZK module that:

Stores ID/Income ACDC credentials with commitments,

Generates ZK range proofs on-device,

Shares a proof to a web verifier app that checks issuer DID, revocation, and proof validity.

Code on GitHub (MIT/Apache). Test via Veridian Sandbox + hosted verifier demo; mobile test via TestFlight/Play Beta.

Describe realistic measures of success, ideally with on-chain metrics.

MVP shipped (wallet ZK module + verifier)

Pilot: ≥20 users, ≥2 verifiers, ≥50 successful proofs

ZK perf: ≤5s proving on mid-range phone; ≤10KB proof; ≤100ms verify

On-chain: ≥3 issuer DIDs anchored; ≥2 schema/def hashes recorded; revocation/status txs exercised (≥10)

[Your Project and Solution] Solution

Please describe your proposed solution and how it addresses the problem

We propose to build a privacy-preserving credential system on Cardano that enables tenants to prove eligibility (e.g., income below a threshold, age above a minimum) without revealing sensitive personal data. This addresses the current gap in social housing and rental processes, where applicants must expose documents such as payslips, tax records, and IDs — often disclosing far more than necessary.

Core Approach

Self-Sovereign Credentials with Hidden Attributes

Tenants obtain two reusable base credentials:

• Identity/KYC credential (from a government ID authority or KYC provider).

• Income credential (from employer, tax authority, or bank).

Instead of storing raw values (birth date, salary), attributes are encoded as Pedersen commitments — cryptographic envelopes that are binding (cannot be altered) and hiding (reveal nothing).

Zero-Knowledge Proofs (ZKPs)

Tenants generate a ZK range proof when asked to prove eligibility:

• Age ≥ 18: wallet proves birth year commitment meets this condition.

• Income ≤ €40,000: wallet proves the income commitment falls in this range.

Proofs are generated locally on the user’s smartphone (using Bulletproofs or Circom/SnarkJS) and are succinct, non-interactive, and unlinkable.

Verifiers (housing officers, landlords) see only a cryptographic “yes/no” confirmation — never the underlying personal data.

Integration with Cardano’s Veridian Identity Platform

Built on KERI decentralized identifiers and ACDC verifiable credentials.

No personal data on-chain; Cardano is used for anchoring issuer DIDs, credential schema hashes, and revocation registries.

Wallet is extended with a “Prove” flow, allowing tenants to respond to QR-coded proof requests.

Verifier Application

Simple web or mobile interface verifies proofs using issuer DID keys and Cardano-anchored registries.

Inspired by COVID pass scanners: one-tap validation, green checkmark for eligibility met.

Innovation

Privacy-first by design: Unlike traditional identity systems that share attributes, this design enforces data minimization and GDPR compliance.

“Issue once, prove many”: A single credential can satisfy many different proof requests without needing reissuance.

Open-source & interoperable: Circuits, wallet extensions, and verifier tools will be released under MIT/Apache, aligned with W3C/DIF standards.

Flexible pilots & EU-wide relevance: Start with Ireland’s social housing but designed for broader EU applications (employment, creditworthiness, age-restricted services).

Why Cardano

Cardano’s Veridian SSI platform offers a robust DID/VC framework to extend.

Anchoring DIDs and revocation events on Cardano adds a decentralized trust layer without exposing personal data.

This project demonstrates Cardano’s leadership in real-world identity and privacy solutions - a key differentiator versus other chains.

[Your Project and Solution] Impact

Please define the positive impact your project will have on the wider Cardano community

This project has both direct social impact (protecting tenants’ privacy in eligibility checks) and strategic impact for Cardano, positioning the ecosystem as a leader in zero-knowledge identity.

Direct Impact

Privacy protection for citizens: Tenants no longer hand over payslips, IDs, and other documents; instead, they share cryptographic proofs. Sensitive data stays on the user’s device.

Reduced risk for agencies/landlords: Agencies avoid handling/retaining large volumes of personal data, lowering GDPR liability and compliance costs.

Efficiency gains: Verification reduces to an instant cryptographic check, streamlining eligibility assessments.

Trust & inclusion: By making verification less invasive, more citizens are likely to engage with housing and social programs.

Impact on the Cardano Ecosystem

Showcasing Cardano in government services: A real pilot in Irish social housing demonstrates Cardano solving a tangible public-service problem. This strengthens credibility with regulators, municipalities, and EU innovation funds.

Driving SSI adoption on Cardano: Every tenant onboarded receives a Cardano-based DID and credential, expanding the base of digital identity users.

Reusable infrastructure: The ZK modules and verifier app are open-source, enabling other Catalyst projects or developers to add privacy-preserving proofs to their dApps.

Ecosystem differentiation: Few blockchains combine self-sovereign identity with zero-knowledge proofs in production pilots. This strengthens Cardano’s position as a platform for digital trust infrastructure.

Community engagement: By contributing code, circuits, and documentation, the project will stimulate collaboration across the Catalyst Identity & Security challenge.

Long-Term Potential

Cross-sector applications: Beyond housing, the same approach can be applied to:

• Employment verification (prove employed without revealing salary).

• Credit checks (prove creditworthiness without exposing full score).

• Age-gated commerce (prove over 18 without disclosing DOB).

EU-wide alignment: The solution anticipates eIDAS 2.0 and European Digital Identity standards, ensuring Cardano can interoperate with future EU identity frameworks.

[Your Project and Solution] Capabilities & Feasibility

What is your capability to deliver your project with high levels of trust and accountability? How do you intend to validate if your approach is feasible?

Blockia Labs is an applied R&D studio headquartered in Estonia. Our focus is on Digital Identity, Blockchain, and Cryptography, and we bring a track record of building prototypes in regulated environments.

Partnerships:

• Cardano Foundation’s Identity Team: we have initiated collaboration with Veridian’s maintainers and received positive guidance.

• Pilot Stakeholders: discussions with Irish housing actors are underway; in pilot, Blockia can act as interim issuer if official issuers lag.

Feasibility of Approach

Reuse of Open Infrastructure

Build on Veridian wallet & SDK (already open-sourced by Cardano Foundation).

Use KERI DIDs and ACDC credentials as the foundation.

Extend with Pedersen commitments + ZK range proofs (Bulletproofs or Circom).

Anchoring of issuer DIDs, schema hashes, and revocation events on Cardano.

This means we are not reinventing identity infrastructure - we are extending it with privacy-preserving ZK features.

Technical Proof Points

Bulletproofs and Pedersen commitments are battle-tested cryptography (already used in confidential transactions).

ZK range proofs for single numeric values are lightweight, making mobile proving feasible (<5 seconds).

Veridian wallet is modular, allowing integration of proving libraries in Kotlin/Swift.

Verification is trivial (milliseconds) and fits well in web/mobile.

Pilot Validation

A limited pilot (20–30 tenants, 1–2 verifiers) will test usability and performance.

Metrics: proof size, proving time, verifier acceptance.

Regulatory fit validated by running ZK in parallel with current document-based checks.

[Milestones] Project Milestones

Milestone Title

Define schemas, implement commitment issuance

Milestone Outputs

This milestone delivers the foundation of the solution:

Credential Schema Definition – Create two ACDC schemas (Identity/KYC and Income). These will encode sensitive attributes as Pedersen commitments instead of plaintext values. Each schema will be registered with issuer DIDs and anchored on the Cardano testnet for auditability.

Issuance Workflow Prototype – Extend Veridian issuance flow with commitment generation and signing. Issuers will issue credentials embedding commitments (e.g., income_commitment, birthdate_commitment).

Zero-Knowledge Circuits – Develop initial circuits for proving:

Income ≤ threshold (range proof).

Age ≥ threshold (date-to-age comparison).

CLI Demonstrator – Build a command-line prototype where:

An issuer issues a test credential.

A holder generates a ZK proof for a given threshold.

A verifier checks proof validity against issuer DID and schema definition.

Preprod Anchoring – Register issuer DID and schema hash on Cardano preprod to validate blockchain integration.

This milestone ensures the mathematical soundness and technical feasibility of the approach before wallet integration.

Acceptance Criteria

Schemas Completed: Two ACDC schemas (Identity, Income) are defined, documented, and published in GitHub repo.

Commitment Issuance: Issuance workflow modified to embed Pedersen commitments; test credentials successfully issued.

Circuits Functional: Initial ZK circuits compile and successfully generate proofs for sample data.

CLI Prototype Works:

Input: sample credential with hidden attribute.

Output: valid proof confirming threshold condition.

Verifier accepts valid proof and rejects altered/fake proofs.

Cardano Preprod Integration: At least one issuer DID and one schema hash registered on Cardano Preprod.

Documentation: Public design document explains schema, commitments, and proof logic.

Evidence of Completion

GitHub repository containing schemas, circuits, CLI prototype code.

Demo video showing issuance - proof generation - verification.

Transaction hash links showing DID and schema anchoring on Cardano preprod.

Public design document published in repo (or GitHub Pages).

Delivery Month

2

Cost

25000

Progress

30 %

Milestone Title

Wallet & Verifier MVP

Milestone Outputs

This milestone delivers the minimum viable product for user interaction and verification:

Wallet Integration

Extend the open-source Veridian wallet (Android/iOS) with a Prove flow.

Holder can select Identity/Income credentials and generate zero-knowledge proofs in response to proof requests.

Proof generation uses the circuits from Milestone 1 (compiled into WASM/SDK).

UX/UI includes progress indicators and confirmation prompts.

Verifier Portal/App

Build a lightweight web portal where verifiers can:

• Scan QR codes or paste proof packages.

• Validate issuer DID signature.

• Verify ZK proof correctness.

Return a clear result (“Pass/Fail: criteria met”).

End-to-End Flow

Issue credential - Wallet generates proof - Verifier checks proof.

All steps executed in real time on mobile + web.

Community Release

Distribute wallet MVP through TestFlight (iOS) and Play Beta (Android).

Host verifier portal for public testing.

Open-source code for wallet extension and verifier published to GitHub.

This milestone demonstrates practical usability of privacy-preserving proofs on Cardano.

Acceptance Criteria

Wallet Functionality:

Users can import valid Identity/Income credentials.

Proof generation completes successfully for thresholds (age ≥18, income ≤ test limit).

Proof size ≤10 KB; proving time ≤5 seconds on mid-range phone.

Verifier Functionality:

Portal verifies issuer DID against anchored registry.

Valid proofs accepted, invalid/altered proofs rejected.

Verification completes in <100 ms.

End-to-End Flow Demonstrated:

Full cycle from credential issuance to verification works without manual intervention.

Video demo shows real use on mobile + web.

Community Release:

Wallet MVP published on TestFlight and Play Beta.

Verifier portal accessible via HTTPS.

Source code released under MIT license.

Evidence of Completion

Public GitHub repositories with wallet extension code and verifier portal.

Demo video showing end-to-end proof verification with wallet + portal.

Live verifier portal URL for community access.

Screenshots of wallet MVP in TestFlight/Play Beta.

Documentation of proof performance benchmarks (time, size, verification speed).

Delivery Month

4

Cost

25000

Progress

60 %

Milestone Title

Pilot Deployment & Final Close-Out

Milestone Outputs

This milestone validates the solution in a real-world context and closes out the Catalyst project with open-source release and reporting:

Pilot Execution

Conduct pilot with 15–20 tenants and 1–2 verifiers (e.g., housing officers/landlords in Ireland).

Tenants use wallet to generate zero-knowledge proofs; verifiers confirm eligibility via the verifier portal.

Run verification in parallel with traditional document checks to validate correctness and trust.

Data Collection & Metrics

Collect proof performance metrics:

• Average proof generation time on mobile.

• Average proof size.

• Verification time on verifier portal.

Collect qualitative feedback from tenants (ease of use, trust) and verifiers (clarity, efficiency).

Documentation & Open-Source Release

Publish final versions of wallet extension, verifier app, and ZK circuits under MIT license.

Provide technical documentation (schemas, architecture, proof logic) and user guides (wallet usage, verifier instructions).

Final Catalyst Deliverables

Final Project Report summarizing outcomes, pilot results, and roadmap for EU scaling.

Video Demonstration showing a tenant proving eligibility with ZK in real-time.

This milestone ensures both real-world validation and transparent closure for the Catalyst community.

Acceptance Criteria

Pilot Completed: At least 15 tenants and 1 verifier successfully perform eligibility checks using ZK proofs.

Accuracy Validated: Proof-based verification outcomes match traditional checks with 100% consistency.

Performance Benchmarked:

Proof generation ≤5 seconds on mid-range smartphones.

Proof size ≤10 KB.

Verification ≤100 ms.

Feedback Collected: Documented survey/interview responses from both tenants and verifiers.

Open-Source Release: GitHub repos with wallet, verifier, and circuits updated with final production code and documentation.

Final Deliverables Submitted: Project close-out report (text) and demonstration video uploaded to Catalyst.

Evidence of Completion

Final GitHub repositories with code and documentation.

Published final project report (PDF/Markdown).

Pilot report with metrics, survey results, and lessons learned.

Screenshots/videos of pilot.

Public YouTube/Vimeo video demo submitted to Catalyst close-out.

Delivery Month

6

Cost

25000

Progress

100 %

[Final Pitch] Budget & Costs

Please provide a cost breakdown of the proposed work and resources

Total Requested: 75,000 ADA

Duration: 6 months

The budget is lean and designed to cover development, testing, and pilot delivery while ensuring value for money. Blockia Labs will supplement Catalyst funding with internal resources and in-kind contributions (infrastructure, management time).

Breakdown

1. Development (45,000 ADA)

Zero-Knowledge Developer (ZKP Specialist): Design and implement Pedersen commitments, Bulletproof circuits, and Circom integration.

Mobile Developer (Wallet Integration): Extend Veridian wallet with “Prove” flow and mobile proof generation.

Backend/Blockchain Developer: Implement DID anchoring, schema registration, and revocation registry on Cardano testnet/mainnet.

Includes coding, integration, and internal QA.

1. Testing & Pilot Deployment (12,000 ADA)

Pilot setup with 15–20 tenants and 1–2 verifiers.

Hosting and infrastructure for verifier portal and testnet nodes.

User stipends/incentives for pilot participants.

Workshops and feedback collection with housing partners.

1. Security & Expert Review (10,000 ADA)

Engage external cryptography expert to review circuits and code.

Validate that ZK proofs are sound and commitment integration secure.

1. Project Management & Documentation (8,000 ADA)

Coordination, reporting, and compliance with Catalyst updates.

Technical documentation, user guides, and onboarding materials.

Final close-out reporting and video production

[Final Pitch] Value for Money

How does the cost of the project represent value for the Cardano ecosystem?

Total Request: 75,000 ADA over 6 months

This proposal represents strong value for the Catalyst community because it delivers a working, open-source privacy module for Cardano identity, validated in a real-world pilot, for under 100k ADA.

Why It’s Cost-Effective

Focused Scope: The budget is tightly scoped to 3 milestones (prototype, MVP, pilot) - each with measurable outputs, ensuring Catalyst sees results within 6 months.

Lean Team: Core work is handled by 4 senior team members with direct Catalyst delivery experience, supported by contracted specialists only where needed.

Reuse of Existing Infrastructure: We extend Veridian wallet (already open-source) and integrate battle-tested cryptography (Pedersen commitments, Bulletproofs), avoiding costly reinvention.

Return on Investment for Cardano

Open-Source Assets: All circuits, wallet code, and verifier apps are published under MIT liceses, reusable by other dApps, Catalyst projects, or enterprises.

Demonstrated Real-World Pilot: A working proof with tenants and verifiers showcases Cardano in government/public service contexts, increasing ecosystem credibility.

Multiplier Effect: Once wallet ZK capabilities exist, they can be repurposed for credit checks, employment verification, or age-restricted commerce — lowering future project costs.

Community Leverage: For 75k ADA, Catalyst seeds infrastructure that could attract government adoption, EU digital identity alignment, and enterprise partnerships.

Efficiency Measures

Milestone-based delivery ensures funds are tied to outputs, not effort alone.

In summary, for a modest 75k ADA investment, the Cardano community gains a privacy-preserving SSI innovation, a pilot showcase, and reusable open-source tools - high leverage at low cost.

[Required Acknowledgements] Consent & Confirmation

Terms and Conditions:

Yes