🧩 Zikuani Architecture:

1. Overview

This document outlines the architecture of Zikuani, a privacy-preserving identity verification system that extracts and validates information from the mobile driver's identity (mDL) using zero-knowledge (ZK) proofs, and verifies these proofs through Soroban smart contracts on the Stellar blockchain.

The objective is to enable secure and compliant identity verification where users can prove authenticity without disclosing personal information.

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2. Components

Layer	Component	Description
Credential Source	mDL App (ISO/IEC 18013-5)	Provides verified identity data and certificates signed by government authorities.
Extraction Module (Zikuani Bridge)	Extracts mDL data via NFC or QR; validates government-issued signatures and certificates.
ZK Prover Device / App	Generates zero-knowledge proofs from hashed mDL data using Circom
Zikuani Wallet	Stores hashed credentials and ZK proofs; interacts with Soroban for verification.
Soroban Smart Contract	Verifies ZK proofs on Stellar’s WASM-based contract platform; marks verified users on-chain.
Verifier Applications	dApps that query verification status on Stellar.

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3. Data and Process Flow

Step 1 – mDL Data Extraction

1. The user opens Zikuani Wallet.
2. The app connects to the mDL via Deep link, QR or NFC (ISO/IEC 18013-5 interface).
3. The mDL provides:
   • Signed identity data (e.g., name, date of birth, identity number).
   • X.509 certificate chain confirming government authority.

Step 2 – Proof Generation (on Device)

1. Commitment and verification conditions (e.g., “over 18”, “identity valid”)

Step 4 – On-Chain Verification (Soroban)

1. The wallet calls the Soroban contract:

   verify_identity(proof, public_inputs, verifier_pubkey)
2. The contract runs an embedded ZK verifier (Groth16).
3. If the proof is valid, the contract stores verification:

   VerifiedIdentities.put(address, true)

Step 5 – Verification by Third Parties

Other Stellar-based applications or DAOs can query:

is_verified(user_address)

to confirm identity validity without accessing private details.

4. Trust and Security Model

Layer	Trust Anchor	Description
mDL Issuer	Digital certificate authority	Ensures authenticity of issued credentials.
Zikuani Bridge	Validates signatures locally	Prevents tampering or fake credentials.
ZK Prover	Local device	Witness data never leaves the user’s control.
Soroban Contract	On-chain, open-source verifier	Deterministic, auditable verification.

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6. Architecture Diagram

 ┌───────────────────────────────┐
 │          mDL System           │
 │  ───────────────────────────  │
 │  Govt CA + Issuer certs + mDL │
 └───────────────┬───────────────┘
                 │ (NFC/QR 18013-5)
                 ▼
 ┌────────────────────────────────────────┐
 │        Zikuani Mobile Wallet           │
 │ Validate mDL → Hash Attributes → Store │
 └───────────────┬────────────────────────┘
                 │ Secure Transfer (BLE/API)
                 ▼
 ┌────────────────────────────────────────┐
 │     ZK Prover Device / Service         │
 │ Circom→ Generate Proof                 │
 └───────────────┬────────────────────────┘
                 │ proof, public_inputs
                 ▼
 ┌────────────────────────────────────────┐
 │   Soroban Smart Contract (Stellar)     │
 │ VerifyProof() → mark user as verified  │
 └───────────────┬────────────────────────┘
                 │
                 ▼
 ┌────────────────────────────────────────┐
 │  dApps / DAOs / Exchanges (Verifiers)  │
 │  Query is_verified(address) → boolean  │
 └────────────────────────────────────────┘

C1 — Issuer · Holder · Verifier

C2 — Technical Architecture

C3 — Soroban Verifier Contract

7. Technology Stack

Layer	Technology	Notes
ZK proof system	Groth16 (zk-SNARK)	Constant-size proofs, fast on-chain verification
Elliptic curve	BN254 (alt-bn128)	Native Soroban Protocol 25 host functions
Hash function	Poseidon	ZK-friendly; Protocol 25 native
Circuit language	Circom 2.x	Compiles to R1CS for Groth16
Smart contract	Rust / Soroban SDK	wasm32v1-none target — contracts/zk_verifier/
Blockchain	Stellar / Soroban	Protocol 25 (X-Ray) — BN254 + Poseidon as host functions
Mobile application	Android SDK, JavaScript	Identity Wallet
Proof serialization	TypeScript	Groth16 JSON proof → Soroban byte arrays
Identity standard	ISO/IEC 18013-5 (mDL)	International mobile Driver's License — 30+ countries

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8. Key Benefits

• Privacy-preserving: Only zero-knowledge proofs reach the blockchain.
• Compliant: Tied to government-issued mDL certificates.
• Efficient: Soroban’s WASM environment supports ZK verification with low gas cost.
• Interoperable: dApps and DAOs on Stellar can natively check verification status.