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MadaBank Security Architecture

Overview

MadaBank implements multiple layers of security to protect user data and prevent unauthorized access. This document outlines our security measures and compliance with banking industry standards.

Security Layers

1. Authentication & Authorization

JWT-Based Authentication:

  • RS256 algorithm for token signing
  • 1-hour token expiration
  • Secure token storage requirements for clients
  • Token refresh mechanism

Password Security:

  • bcrypt hashing with cost factor 12
  • Minimum 8 characters required
  • Password strength validation
  • Password reset with email verification

2. Encryption

Data at Rest:

  • Database encryption: AES-256
  • Card numbers: AES-256-GCM with unique IV per record
  • CVV: Encrypted separately from card numbers
  • Sensitive fields: Application-level encryption
  • Key rotation: Every 90 days

Data in Transit:

  • TLS 1.3 enforced
  • HSTS headers enabled
  • Certificate pinning recommended for mobile apps

Key Management:

  • AWS Secrets Manager for production
  • Environment variables for development
  • Separate keys per environment
  • No keys in source code

3. Rate Limiting

Endpoint-Specific Limits:

Endpoint Limit Window
Auth (login/register) 5 requests 1 minute
Transactions 10 requests 1 minute
General API 100 requests 1 minute

Rate Limit Headers:

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 95
X-RateLimit-Reset: 1234567890
Retry-After: 60

IP-Based Rate Limiting:

  • Tracks requests per IP address
  • Automatic blocking after threshold exceeded
  • Redis-backed for distributed systems

User-Based Rate Limiting:

  • Tracks requests per authenticated user
  • Prevents account abuse
  • Independent from IP limits

4. DDoS Protection

Application Layer:

  • Rate limiting per IP
  • Rate limiting per user
  • Suspicious pattern detection
  • Automatic IP blocking

Infrastructure Layer (AWS):

  • CloudFront CDN
  • AWS Shield Standard
  • WAF rules:
    • Rate limiting: 2000 req/5min per IP
    • SQL injection prevention
    • XSS prevention
    • Geo-blocking (optional)

Attack Detection:

  • Real-time traffic monitoring
  • Automatic alerting for anomalies
  • IP blocking for > 1000 req/min
  • Global emergency mode for coordinated attacks

5. Transaction Security

ACID Compliance:

  • Database transactions for all financial operations
  • Row-level locking prevents race conditions
  • Rollback on any failure
  • Audit trail for all transactions

Idempotency:

  • Unique idempotency keys required
  • Duplicate prevention
  • Safe retry mechanism
  • 24-hour key expiration

Authorization:

  • Account ownership verification
  • Multi-step validation
  • Balance checks before execution

6. Audit Logging

What We Log:

  • All authentication attempts
  • All transactions (success and failure)
  • Account modifications
  • Card operations
  • Security events (blocks, suspicious activity)

Log Format:

{
  "event_id": "uuid",
  "timestamp": "ISO8601",
  "user_id": "uuid",
  "action": "TRANSFER_INITIATED",
  "resource": "account:12345",
  "ip_address": "192.168.1.1",
  "user_agent": "iOS/17.2",
  "status": "success",
  "metadata": {}
}

Log Retention:

  • Development: 7 days
  • Production: 7 years (compliance requirement)

7. Card Management

Storage:

  • Card numbers: Encrypted with AES-256-GCM
  • CVV: Encrypted separately
  • Never stored in logs
  • Never transmitted in API responses (except on explicit request with password)

Access Control:

  • Password verification required for full card details
  • Rate limited to prevent brute force
  • Masked display by default (only last 4 digits)

Card Number Validation:

  • Luhn algorithm validation
  • Format validation
  • Expiry date validation

8. Network Security

VPC Configuration:

  • Private subnets for application and database
  • Public subnets only for load balancer
  • NAT gateways for outbound traffic
  • VPC Flow Logs enabled

Security Groups:

  • Least privilege principle
  • ALB: Only 80/443 from internet
  • ECS: Only 8080 from ALB
  • RDS: Only 5432 from ECS
  • Redis: Only 6379 from ECS

Compliance

ISO 27001 Concepts Implemented

✅ Access Control (A.9):

  • Strong authentication
  • Role-based access control
  • Session management

✅ Cryptography (A.10):

  • Encryption at rest and in transit
  • Key management
  • Secure protocols

✅ Physical Security (A.11):

  • AWS data center security
  • No physical access required

✅ Operations Security (A.12):

  • Audit logging
  • Monitoring and alerting
  • Backup and recovery

✅ Communications Security (A.13):

  • Network segmentation
  • Secure data transfer

✅ Incident Management (A.16):

  • Automated detection
  • Alerting mechanisms
  • Audit trails

CMMI Concepts Implemented

✅ Configuration Management:

  • Infrastructure as Code (Terraform)
  • Version control (Git)
  • Change management (PR reviews)

✅ Quality Assurance:

  • Automated testing (CI/CD)
  • Code review process
  • Security scanning

✅ Process Definition:

  • Documented procedures
  • Standard deployment process
  • Monitoring and metrics

Security Best Practices

For API Consumers

Authentication:

# Include JWT token in all requests
curl -H "Authorization: Bearer <token>" \
  https://api.madabank.com/api/v1/accounts

Rate Limiting:

  • Monitor rate limit headers
  • Implement exponential backoff
  • Cache responses when appropriate

Error Handling:

  • Never log sensitive data
  • Handle errors gracefully
  • Don't expose internal details to users

For Mobile App Development

Token Storage:

  • iOS: Store in Keychain
  • Android: Store in KeyStore
  • Never in UserDefaults/SharedPreferences

Certificate Pinning:

// iOS Example
let session = URLSession(
  configuration: .default,
  delegate: PinningDelegate(),
  delegateQueue: nil
)

Biometric Authentication:

  • Implement Face ID/Touch ID
  • Require for card details access
  • Require for large transactions

Incident Response

Suspected Security Breach

  1. Immediate Actions:

    • Block affected accounts
    • Revoke compromised tokens
    • Enable emergency rate limiting

  2. Investigation:

    • Review audit logs
    • Analyze attack patterns
    • Identify affected users

  3. Remediation:

    • Force password resets
    • Update security rules
    • Patch vulnerabilities

  4. Communication:

    • Notify affected users
    • Report to authorities if required
    • Document lessons learned

Security Contacts

Vulnerability Disclosure

We welcome responsible security researchers:

  1. Email security@madabank.com
  2. Include detailed description
  3. Provide steps to reproduce
  4. Allow 90 days for fix before public disclosure

Bug Bounty Program: Coming soon

Last Updated: January 2026
Version: 1.0