# WIA-FIN-013: Mobile Payment Standard 📱

> **Universal standard for mobile payment systems, NFC, QR codes, wallets, and biometric authentication**

[![Version](https://img.shields.io/badge/version-1.0.0-green.svg)](https://github.com/WIA-Official/wia-standards)
[![Standard](https://img.shields.io/badge/standard-WIA--FIN--013-green.svg)](https://wiastandards.com)
[![License](https://img.shields.io/badge/license-MIT-blue.svg)](LICENSE)
[![Certified](https://img.shields.io/badge/WIA-Certified-gold.svg)](https://cert.wiastandards.com)

---

## 📋 Table of Contents

1. [Overview](#overview)
2. [Key Features](#key-features)
3. [Quick Start](#quick-start)
4. [Architecture](#architecture)
5. [Payment Technologies](#payment-technologies)
6. [Data Formats](#data-formats)
7. [API Reference](#api-reference)
8. [Security](#security)
9. [Examples](#examples)
10. [Integration Guide](#integration-guide)
11. [Contributing](#contributing)
12. [License](#license)

---

## 🌟 Overview

The **WIA-FIN-013 Mobile Payment Standard** provides a comprehensive framework for building, integrating, and certifying mobile payment applications. It standardizes data formats, APIs, protocols, and integration patterns across NFC, QR code, wallet, P2P, and biometric payment methods.

### Philosophy: 홍익인간 (弘益人間)

> **"Benefit All Humanity"**

Just as mobile payments democratize access to financial services, the WIA Mobile Payment Standard democratizes access to payment technology by providing universal standards that work across all platforms and regions.

### What is Mobile Payment?

Mobile payment refers to any payment transaction completed through a mobile device (smartphone, tablet, smartwatch). It encompasses:

- **NFC Payments:** Contactless tap-to-pay (Apple Pay, Google Pay, Samsung Pay)
- **QR Code Payments:** Camera-based scanning (Alipay, WeChat Pay, PayTM)
- **Mobile Wallets:** Digital storage of payment cards and cash
- **P2P Transfers:** Person-to-person money transfers (Venmo, Zelle, Cash App)
- **Biometric Authentication:** Fingerprint, face recognition for secure payments
- **USSD Payments:** Feature phone compatibility for emerging markets

### Market Overview

| Metric | Value |
|--------|-------|
| **Global Transaction Volume** | $10+ trillion annually |
| **Active Users** | 2.8+ billion globally |
| **Merchants** | 100+ million accepting mobile payments |
| **Growth Rate** | 45% CAGR (2020-2025) |
| **Average Transaction Time** | < 1 second (NFC) |

---

## ✨ Key Features

### 🎯 Universal Compatibility

- **Multi-Technology:** NFC, QR codes, wallets, P2P, biometric
- **Multi-Platform:** iOS, Android, Web, wearables
- **Multi-Region:** Global coverage with local optimizations
- **Multi-Language:** SDKs in TypeScript, Python, Go, Swift, Kotlin

### 📊 Standardized Data Formats

- JSON schemas for all payment data structures
- Consistent naming conventions across methods
- Built-in validation and error handling
- Versioned schemas for backward compatibility

### 🔌 Comprehensive APIs

- RESTful endpoints for all operations
- WebSocket support for real-time updates
- GraphQL support for flexible queries
- Rate limiting and authentication
- Comprehensive error codes

### 🔐 Security First

- End-to-end encryption (TLS 1.3+)
- Payment tokenization (EMV standards)
- Biometric authentication
- PCI DSS compliance
- Fraud detection integration
- GDPR and privacy compliance

### 🌐 Global Standards

- ISO 20022 messaging compliance
- EMVCo specifications
- PCI DSS 4.0 requirements
- GDPR data protection
- PSD2 compatibility (EU)
- Local regulatory compliance

---

## 🚀 Quick Start

### Installation

```bash
# TypeScript/JavaScript
npm install @wia/mobile-payment-sdk

# Python
pip install wia-mobile-payment-sdk

# Go
go get github.com/WIA-Official/wia-mobile-payment-go

# Swift (iOS)
pod 'WIAMobilePayment'

# Kotlin (Android)
implementation 'com.wia:mobile-payment:1.0.0'
```

### Basic Usage (TypeScript)

```typescript
import { WIAMobilePayment } from '@wia/mobile-payment-sdk';

// Initialize SDK
const payment = new WIAMobilePayment({
  apiKey: 'wia_live_abc123...',
  environment: 'production'
});

// Process NFC payment
const result = await payment.processPayment({
  amount: 99.99,
  currency: 'USD',
  method: 'nfc',
  merchantId: 'merchant_xyz789',
  deviceId: 'dev_abc123'
});

if (result.success) {
  console.log('Payment successful!', result.data.transactionId);
} else {
  console.error('Payment failed:', result.error);
}
```

### Python Example

```python
from wia_mobile_payment import WIAMobilePayment

# Initialize
payment = WIAMobilePayment(api_key='wia_live_abc123...')

# Process payment
result = payment.process_payment(
    amount=99.99,
    currency='USD',
    method='nfc',
    merchant_id='merchant_xyz789'
)

if result['success']:
    print(f"Payment successful: {result['data']['transactionId']}")
else:
    print(f"Payment failed: {result['error']}")
```

### iOS (Swift) Example

```swift
import WIAMobilePayment

let payment = WIAMobilePayment(apiKey: "wia_live_abc123...")

payment.processPayment(
    amount: 99.99,
    currency: "USD",
    method: .nfc,
    merchantId: "merchant_xyz789"
) { result in
    switch result {
    case .success(let transaction):
        print("Payment successful: \\(transaction.id)")
    case .failure(let error):
        print("Payment failed: \\(error.localizedDescription)")
    }
}
```

---

## 🏗 Architecture

The WIA Mobile Payment Standard follows a four-phase architecture:

### Phase 1: Data Format

Standardized JSON schemas for all mobile payment primitives:

```json
{
  "version": "1.0.0",
  "standard": "WIA-FIN-013",
  "transactionId": "tx_1234567890abcdef",
  "type": "payment",
  "method": "nfc",
  "status": "completed",
  "amount": {
    "value": "99.99",
    "currency": "USD",
    "minorUnits": 2
  },
  "merchant": {
    "id": "merchant_xyz789",
    "name": "Coffee Shop"
  },
  "timestamps": {
    "initiated": "2025-12-25T14:30:00.000Z",
    "completed": "2025-12-25T14:30:02.567Z"
  }
}
```

### Phase 2: API Interface

RESTful endpoints for all operations:

- **POST** `/payments` - Process payment
- **GET** `/payments/:id` - Get transaction details
- **POST** `/payments/:id/refund` - Refund payment
- **POST** `/wallets` - Create wallet
- **POST** `/wallets/:id/payment-methods` - Add payment method
- **POST** `/tokens` - Create payment token
- **POST** `/qr-codes` - Generate QR code
- **POST** `/auth/biometric` - Biometric authentication
- **POST** `/p2p-transfers` - P2P money transfer

### Phase 3: Protocol

Technical protocols and mechanisms:

- **NFC Protocol:** EMV contactless, tokenization, Secure Element
- **QR Code Standard:** Static/dynamic QR, MPM/CPM modes
- **Wallet Protocol:** Token storage, multi-card management
- **Biometric Protocol:** Fingerprint, face recognition, liveness detection
- **P2P Protocol:** Instant transfers, verification, settlement

### Phase 4: Integration

Ecosystem integration patterns:

- Platform SDKs (iOS, Android, Web)
- Payment gateway integration
- Merchant POS integration
- Bank/issuer integration
- Compliance and certification
- Testing and deployment

---

## 💳 Payment Technologies

### NFC (Near Field Communication)

**How it works:**
1. User holds phone near NFC terminal (< 4cm range)
2. Devices establish electromagnetic connection at 13.56 MHz
3. Phone transmits tokenized payment credentials via Secure Element
4. Terminal validates and processes payment
5. Transaction completes in < 1 second

**Platforms:**
- **Apple Pay:** iPhone, Apple Watch (eSE + Face ID/Touch ID)
- **Google Pay:** Android devices (HCE + biometric)
- **Samsung Pay:** NFC + MST for magnetic stripe compatibility

**Security:**
- EMV tokenization replaces real card numbers
- Dynamic cryptogram changes each transaction
- Biometric authentication required
- Works offline (credentials in Secure Element)

### QR Code Payments

**Two Models:**

1. **Merchant-Presented Mode (MPM):** Merchant displays static QR, customer scans
2. **Customer-Presented Mode (CPM):** Customer generates dynamic QR, merchant scans

**Advantages:**
- Zero infrastructure cost (printed QR works)
- Works on any smartphone with camera
- Perfect for small businesses and street vendors
- Can encode additional data (receipts, loyalty)

**Popular Platforms:**
- Alipay (China): 1.3+ billion users
- WeChat Pay (China): 900+ million users
- PayTM (India): 350+ million users
- Mercado Pago (Latin America): 100+ million users

### Mobile Wallets

Digital wallets store payment credentials, loyalty cards, tickets, and more:

**Features:**
- Card storage and management
- Transaction history and analytics
- Loyalty programs integration
- P2P transfers
- Bill payment and top-ups
- Merchant offers and coupons

**Types:**
- **Closed Wallets:** Store-specific (Starbucks, Amazon)
- **Semi-Closed:** Limited merchant network (PayTM)
- **Open Wallets:** Universal acceptance (Apple Pay, Google Pay)

### P2P Transfers

Peer-to-peer money transfers for:
- Bill splitting among friends
- Rent payments between roommates
- Gift giving (digital red packets)
- Freelance/gig work payments

**Popular Services:**
- Venmo (USA): Social payments
- Zelle (USA): Bank-to-bank instant transfers
- Cash App (USA): Bitcoin integration
- WeChat Pay (China): Social ecosystem

### Biometric Authentication

**Methods:**

| Method | Accuracy | Speed | Use Case |
|--------|----------|-------|----------|
| Fingerprint | 99.8% | < 1 sec | Most common |
| Face Recognition | 99.9% | < 1 sec | iPhone Face ID |
| Iris Scan | 99.99% | 1-2 sec | High security |
| Voice Recognition | 95% | 2-3 sec | Phone banking |

**Security Features:**
- Liveness detection prevents spoofing
- Template hashing (biometric data never stored)
- Secure Enclave/TEE processing
- Multi-factor authentication

---

## 📊 Data Formats

### Transaction

```typescript
interface Transaction {
  version: string;
  standard: 'WIA-FIN-013';
  transactionId: string;
  type: 'payment';
  method: 'nfc' | 'qr_code' | 'card' | 'wallet' | 'bank_transfer' | 'crypto';
  status: 'initiated' | 'authorizing' | 'authorized' | 'completed' | 'failed' | 'declined' | 'cancelled' | 'refunded';
  amount: {
    value: string;
    currency: string;
    minorUnits: number;
  };
  merchant?: {
    id: string;
    name: string;
    category?: string;
  };
  customer?: {
    customerId: string;
    email?: string;
    phone?: string;
  };
  paymentMethod?: {
    type: 'card' | 'bank_account' | 'wallet';
    brand?: string;
    last4?: string;
    tokenId?: string;
  };
  authentication?: {
    method: 'biometric' | 'pin' | 'password' | 'otp';
    type?: 'fingerprint' | 'face_id' | 'iris' | 'voice';
    timestamp: string;
  };
  timestamps: {
    initiated: string;
    authorized?: string;
    completed?: string;
  };
  metadata?: Record<string, any>;
}
```

See [spec/PHASE-1-DATA-FORMAT.md](spec/PHASE-1-DATA-FORMAT.md) for complete schemas.

---

## 🔌 API Reference

### Base URL

```
Production: https://api.wiastandards.com/mobile-payment/v1
Test: https://api-test.wiastandards.com/mobile-payment/v1
Sandbox: https://api-sandbox.wiastandards.com/mobile-payment/v1
```

### Authentication

All requests require an API key:

```http
Authorization: Bearer <access_token>
X-API-Key: wia_live_abc123...
```

### Rate Limits

| Tier | Requests/min | Requests/day | Price |
|------|--------------|--------------|-------|
| Free | 60 | 10,000 | $0 |
| Developer | 300 | 100,000 | $49/mo |
| Professional | 1,000 | 1,000,000 | $199/mo |
| Enterprise | Unlimited | Unlimited | Custom |

### Endpoints

#### Process Payment

```http
POST /payments
Content-Type: application/json

{
  "amount": {
    "value": "99.99",
    "currency": "USD"
  },
  "method": "nfc",
  "merchantId": "merchant_xyz789",
  "deviceId": "dev_abc123"
}
```

#### Create Wallet

```http
POST /wallets
Content-Type: application/json

{
  "userId": "user_xyz789",
  "type": "mobile_wallet",
  "currency": "USD"
}
```

#### Generate QR Code

```http
POST /qr-codes
Content-Type: application/json

{
  "merchantId": "merchant_xyz789",
  "amount": {
    "value": "99.99",
    "currency": "USD"
  },
  "type": "dynamic",
  "expiresIn": 300
}
```

See [spec/PHASE-2-API.md](spec/PHASE-2-API.md) for complete API documentation.

---

## 🔒 Security

### Encryption Standards

- **In Transit:** TLS 1.3 minimum
- **At Rest:** AES-256 encryption
- **Key Exchange:** RSA-4096 or ECDHE
- **Hashing:** SHA-256 or better

### Tokenization

Payment tokenization replaces real card numbers with device-specific tokens:

```
Real Card:  4111 1111 1111 1111
Token:      4900 0012 3456 7890
```

- Token valid only for specific device
- Dynamic cryptogram changes each transaction
- Tokens can be remotely suspended/deleted
- Real PAN never leaves issuer systems

### PCI DSS Compliance

Required security measures:
- Never store CVV/CVV2
- Tokenize all card numbers
- Encrypt cardholder data
- Maintain secure network
- Regular security audits
- Access control and monitoring

### Fraud Prevention

- Real-time transaction monitoring
- Velocity checks (transaction frequency)
- Geolocation verification
- Device fingerprinting
- Behavioral analysis
- Machine learning anomaly detection

---

## 💡 Examples

### Example 1: NFC Payment (iOS)

```swift
import PassKit
import WIAMobilePayment

class PaymentViewController: UIViewController, PKPaymentAuthorizationViewControllerDelegate {

    func processNFCPayment() {
        let request = PKPaymentRequest()
        request.merchantIdentifier = "merchant.com.yourapp"
        request.supportedNetworks = [.visa, .masterCard, .amex]
        request.merchantCapabilities = .capability3DS
        request.countryCode = "US"
        request.currencyCode = "USD"

        let item = PKPaymentSummaryItem(
            label: "Total",
            amount: NSDecimalNumber(string: "99.99")
        )
        request.paymentSummaryItems = [item]

        let controller = PKPaymentAuthorizationViewController(paymentRequest: request)!
        controller.delegate = self
        present(controller, animated: true)
    }

    func paymentAuthorizationViewController(
        _ controller: PKPaymentAuthorizationViewController,
        didAuthorizePayment payment: PKPayment,
        handler completion: @escaping (PKPaymentAuthorizationResult) -> Void
    ) {
        // Process payment with WIA SDK
        let wiaPayment = WIAMobilePayment(apiKey: "wia_live_...")

        wiaPayment.processApplePayment(payment: payment) { result in
            switch result {
            case .success(let transaction):
                completion(PKPaymentAuthorizationResult(
                    status: .success,
                    errors: nil
                ))
            case .failure(let error):
                completion(PKPaymentAuthorizationResult(
                    status: .failure,
                    errors: [error]
                ))
            }
        }
    }
}
```

### Example 2: QR Code Payment (Android)

```kotlin
import com.wia.mobilepayment.WIAMobilePayment
import com.wia.mobilepayment.models.*
import kotlinx.coroutines.*

class QRPaymentActivity : AppCompatActivity() {

    private val payment = WIAMobilePayment(apiKey = "wia_live_...")

    fun generateDynamicQR() {
        lifecycleScope.launch {
            try {
                val qrCode = payment.generateQRCode(
                    merchantId = "merchant_xyz789",
                    amount = Amount(
                        value = "99.99",
                        currency = "USD"
                    ),
                    type = QRType.DYNAMIC,
                    expiresIn = 300 // 5 minutes
                )

                // Display QR code
                val bitmap = QRCodeGenerator.generate(qrCode.data.qrCodeId)
                binding.imageView.setImageBitmap(bitmap)

                // Start monitoring for payment
                monitorQRPayment(qrCode.data.qrCodeId)

            } catch (e: Exception) {
                Toast.makeText(this@QRPaymentActivity,
                    "Error: ${e.message}",
                    Toast.LENGTH_SHORT
                ).show()
            }
        }
    }

    private suspend fun monitorQRPayment(qrCodeId: String) {
        while (true) {
            delay(1000) // Poll every second

            val qrCode = payment.getQRCode(qrCodeId)

            if (qrCode.data.scannedCount > 0) {
                // Payment initiated
                Toast.makeText(this,
                    "Payment successful!",
                    Toast.LENGTH_SHORT
                ).show()
                finish()
                break
            }
        }
    }
}
```

### Example 3: Biometric Authentication

```typescript
import { WIAMobilePayment } from '@wia/mobile-payment-sdk';

async function authenticateAndPay() {
  const payment = new WIAMobilePayment({
    apiKey: 'wia_live_abc123...'
  });

  try {
    // Step 1: Authenticate with biometric
    const authResult = await payment.authenticateBiometric({
      method: 'fingerprint',
      allowFallback: true
    });

    if (!authResult.success) {
      throw new Error('Biometric authentication failed');
    }

    console.log('Biometric auth successful, confidence:',
      authResult.data.confidence);

    // Step 2: Process payment
    const paymentResult = await payment.processPayment({
      amount: 99.99,
      currency: 'USD',
      method: 'nfc',
      merchantId: 'merchant_xyz789',
      authenticationId: authResult.data.authenticationId
    });

    if (paymentResult.success) {
      console.log('Payment successful!');
      console.log('Transaction ID:', paymentResult.data.transactionId);
    } else {
      console.error('Payment failed:', paymentResult.error);
    }

  } catch (error) {
    console.error('Error:', error.message);
  }
}
```

### Example 4: P2P Transfer

```python
from wia_mobile_payment import WIAMobilePayment

payment = WIAMobilePayment(api_key='wia_live_abc123...')

# Send money to friend
result = payment.send_p2p_transfer(
    sender_wallet_id='wallet_sender_xyz',
    recipient_wallet_id='wallet_recipient_abc',
    amount=50.00,
    currency='USD',
    message='Lunch money 🍕'
)

if result['success']:
    print(f"Transfer successful!")
    print(f"Transfer ID: {result['data']['transferId']}")
    print(f"Status: {result['data']['status']}")
else:
    print(f"Transfer failed: {result['error']['message']}")
```

---

## 🔗 Integration Guide

### Step 1: Get API Keys

1. Sign up at [https://wiastandards.com](https://wiastandards.com)
2. Navigate to Developer Dashboard
3. Create new application
4. Copy API keys (test and production)

### Step 2: Install SDK

```bash
npm install @wia/mobile-payment-sdk
```

### Step 3: Initialize

```typescript
import { WIAMobilePayment } from '@wia/mobile-payment-sdk';

const payment = new WIAMobilePayment({
  apiKey: 'wia_test_abc123...',
  environment: 'test'
});
```

### Step 4: Implement Payment Flow

1. **User initiates payment**
2. **Authenticate user** (biometric/PIN)
3. **Process payment** (NFC/QR/card)
4. **Handle response** (success/error)
5. **Show confirmation** to user

### Step 5: Test

Use test environment and test card numbers:
- **Visa:** 4111111111111111
- **Mastercard:** 5555555555554444
- **Success:** Amount < $100
- **Decline:** Amount = $100.01

### Step 6: Go Live

1. Complete security review
2. Obtain PCI DSS compliance (if storing cards)
3. Switch to production API keys
4. Deploy with monitoring
5. Register for WIA certification

---

## 🤝 Contributing

We welcome contributions! Here's how:

### Code Contributions

1. Fork the repository
2. Create feature branch (`git checkout -b feature/amazing-feature`)
3. Commit changes (`git commit -m 'Add amazing feature'`)
4. Push to branch (`git push origin feature/amazing-feature`)
5. Open Pull Request

### Documentation

- Improve existing docs
- Add examples and tutorials
- Translate to other languages
- Report errors or unclear sections

### Testing

- Report bugs and issues
- Test integrations with different platforms
- Performance testing
- Security testing

---

## 📜 License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.

```
MIT License

Copyright (c) 2025 WIA (World Certification Industry Association)

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction...
```

---

## 🌐 Resources

### Documentation

- **Main Site:** https://wiastandards.com/mobile-payment
- **API Docs:** https://api.wiastandards.com/docs
- **Ebook:** https://wiabook.com/mobile-payment
- **Simulator:** https://wiastandards.com/mobile-payment/simulator

### Community

- **Discord:** https://discord.gg/wia-standards
- **Forum:** https://forum.wiastandards.com
- **Twitter:** @WIAStandards
- **GitHub:** https://github.com/WIA-Official/wia-standards

### Support

- **Email:** mobile-payment@wiastandards.com
- **Support Portal:** https://support.wiastandards.com
- **Status Page:** https://status.wiastandards.com

---

## 📊 Statistics

![GitHub stars](https://img.shields.io/github/stars/WIA-Official/wia-standards?style=social)
![GitHub forks](https://img.shields.io/github/forks/WIA-Official/wia-standards?style=social)
![GitHub issues](https://img.shields.io/github/issues/WIA-Official/wia-standards)

---

<div align="center">

**홍익인간 (弘益人間)**

**Benefit All Humanity**

---

© 2025 WIA (World Certification Industry Association)

[Website](https://wiastandards.com) • [Documentation](https://docs.wiastandards.com) • [Community](https://discord.gg/wia-standards)

</div>