[CT-05] Build MultiPartyVerificationService

[mftee]

Problem

The current verification model requires only one party to anchor a document. High-value land transactions typically require multiple authorised parties (e.g. seller, buyer, notary) to co-sign before a record is considered confirmed.

Proposed Solution

Create a MultiPartyVerificationService inside contract/module/multi-party/ that tracks multiple verifier signatures for a single document hash.

Acceptance Criteria

• POST /module/multi-party/register accepts document_hash, required_verifiers (array of public keys or identifiers), and stores the requirement in Redis under key multi:{document_hash}
• POST /module/multi-party/sign accepts document_hash and verifier_id, records the signature in Redis, and returns the current signature count and required count
• GET /module/multi-party/status/:document_hash returns: required_count, signed_count, signers (array), and status (PARTIAL or COMPLETE)
• When signed_count reaches required_count the service anchors a MULTI_PARTY_COMPLETE event on Stellar and updates the Redis record
• Returns 404 if no multi-party requirement has been registered for the given hash
• Returns 409 if a verifier attempts to sign a document they have already signed
• Implementation files live inside contract/module/multi-party/

[Ejirowebfi]

@Ejirowebfi has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintainers, I'd like to work on this issue.

I'm a Full Stack Developer with experience across the entire stack — from pixel-accurate frontend UIs to scalable backend APIs and database design. I've shipped production-ready features using Next.js/React + Tailwind on the frontend, and Node.js/Express, PostgreSQL, and REST/GraphQL APIs on the backend.

What I'll deliver

• Component/feature implemented to match the design/spec
• Responsive behavior (mobile + desktop), no layout breakage
• Hover/focus states + accessible semantics
• Clean, reusable components and consistent styling
• RESTful or GraphQL API endpoints (if applicable)
• Database schema design or migrations (if applicable)
• Authentication, authorization, and data validation where needed

Approach

1. Review the design/spec, existing code patterns, and any relevant API contracts
2. Build the UI + interactions on the frontend
3. Implement or update backend logic, routes, and data models as needed
4. Write unit/integration tests for critical paths
5. QA on multiple breakpoints + open a PR with screenshots/video and a summary of backend changes

Stack
Frontend: Next.js · React · TypeScript · Tailwind CSS
Backend: Node.js · Express · PostgreSQL · Prisma / Drizzle
Infra: REST · GraphQL · JWT Auth · Docker · Vercel / Railway

If assigned, I'll start immediately and share progress updates in the PR.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ejirowebfi to this issue.

[dotmantissa]

@dotmantissa has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

I can fix this.
ETA: 1 - 2 hours.

Kindly assign it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @dotmantissa to this issue.

[Ssoleed]

@Ssoleed has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Good day, please I am committed to my work on drips and I assure you the job completion on time .I would love to work on this issue maintainer. Please Assign me and I'll get the job done.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Ssoleed to this issue.

[Sadeequ]

@Sadeequ has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi maintaintainer let me get on this for you, it is similar to the issue i solved earlier.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Sadeequ to this issue.

[drips-wave]

Congratulations, @Sadeequ! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 2, 2026.

🧑‍💻 @Sadeequ: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊