Architecture

 Wallet (Freighter / Albedo / LOBSTR)
        │ sign
        ▼
 ┌──────────────┐   REST + JWT   ┌──────────────┐   RPC   ┌───────────────────┐
 │  Frontend    │ ─────────────▶ │  Backend     │ ──────▶ │ Soroban contracts │
 │  Next.js 15  │                │  NestJS      │         │ (Rust)            │
 └──────────────┘                └──────┬───────┘         └───────────────────┘
        │  ZK proofs (SnarkJS)          │
        ▼                               ├── PostgreSQL (TypeORM)
 ┌──────────────┐                       ├── Redis (cache)
 │ Circom/Groth16│                      ├── IPFS via Pinata (encrypted documents)
 └──────────────┘                       └── Groq (document analysis, fraud checks)

On-chain

Contracts live in contracts/src and build into a single crate (securedata-contracts, soroban-sdk 21.7):

Contract	Responsibility
IdentityRegistry	Registers identities (owner, document hash, IPFS CID), marks them verified or revoked, and owns the upgrade mechanism
VaccinationVerification	Issues, verifies and revokes vaccination credentials; reports vaccination status
Verification	Submits and approves or rejects identity verification proofs; tracks revocations
AccessControl	Grants, extends and revokes time-limited access to resources
DataSharing	Shares documents and credentials between addresses with expiry and re-share rules
Auditing	Audit log, activity tracking and issuer authorization checks

Upgrades

IdentityRegistry uses a proxy pattern with a 24-hour timelock (schedule_upgrade → execute_upgrade), a migration registry, state-hash consistency checks, and an emergency pause (emergency_pause_upgrades).

Off-chain

• Backend (backend/): NestJS REST API under the API_PREFIX (default api/v1) on port 3001. It handles wallet-signature login, JWT auth, PostgreSQL persistence, Redis caching, IPFS uploads and contract calls.
• Frontend (frontend/): Next.js 15, Tailwind, shadcn/ui, with Freighter for the wallet.
• ZK (zk/): Circom circuits proved with SnarkJS and Groth16. See ZK overview.