WhatsApp Echo is built with a privacy-first architecture that prioritizes user data protection and security. This document outlines our security measures, privacy protections, and how to report security vulnerabilities.

• Google OAuth Integration: Secure authentication using Google's OAuth 2.0 flow
• JWT Session Management: NextAuth.js handles secure session tokens
• Role-Based Access Control: Separate admin and user permissions
• Token-Based Background API: SHA256 authentication for background processing
• CSRF Protection: Token-based request validation for all forms

• Zero Transcript Logging: Voice transcript content is NEVER logged to console, files, or monitoring systems
• In-Memory Processing: Audio files are processed entirely in memory without disk writes
• No Persistent Storage: Voice transcripts are not stored in database - only delivered via email
• Metadata-Only Logging: System logs contain only technical data (file size, processing time, success/failure)
• Privacy-Safe Error Handling: Error objects contain only technical metadata, never transcript content

• File Type Validation: Strict audio format checking (M4A, MP3, WAV, OGG)
• File Size Limits: Maximum 15MB file size to prevent abuse
• Email Format Validation: Proper email address validation
• SQL Injection Prevention: Parameterized queries for all database operations
• XSS Prevention: Input sanitization and Content Security Policy headers

• Per-User Rate Limiting: 5 voice notes per minute per user
• API Rate Limiting: 100 requests per minute per IP for general APIs
• Admin API Protection: 30 requests per minute for admin operations
• Authentication Rate Limiting: 10 login attempts per 15 minutes per IP
• In-Memory Rate Limiting: Fast, efficient rate limiting with automatic cleanup

• Content Security Policy (CSP): Prevents XSS attacks
• X-Frame-Options: Prevents clickjacking attacks
• X-Content-Type-Options: Prevents MIME type sniffing
• Strict-Transport-Security: Enforces HTTPS connections
• X-XSS-Protection: Browser XSS protection

• TLS Encryption: All connections use HTTPS with automatic certificate management
• Environment Variable Protection: All sensitive credentials stored in environment variables
• Secure Background Processing: Token-based authentication for background enhancement API
• Webhook Security: Mailgun HMAC signature verification (implementation pending)

• ❌ Voice transcript content - Never stored in database or logs
• ❌ Audio files - Processed in memory only, never written to disk
• ❌ Sensitive user data - Only metadata and account information stored
• ❌ Processing content - AI enhancement results not logged or stored

• ✅ User account information - Google email, approval status, created date
• ✅ Processing metadata - File size, duration, processing time, success/failure
• ✅ User preferences - Enhancement settings (cleanup, summary options)
• ✅ Technical logs - Performance metrics, error counts (no content)

1. Immediate Delivery: Transcripts delivered via email, not stored on servers
2. Memory-Only Processing: Audio files processed entirely in memory
3. Content Exclusion: Monitoring systems (Sentry) exclude transcript content
4. Minimal Data Collection: Only essential metadata collected
5. Automatic Cleanup: In-memory data automatically garbage collected

• Sentry Integration: Error monitoring with transcript content exclusion
• Performance Monitoring: Function execution times and memory usage
• Rate Limit Monitoring: Abuse detection and prevention
• Failed Authentication Tracking: Login attempt monitoring

• Database Operations: All user and preference changes logged
• Authentication Events: Login/logout events tracked
• Admin Actions: User approval/revocation actions logged
• Processing Metrics: Voice note processing success/failure rates

If you discover a security vulnerability, please report it responsibly:

1. Email: Send details to the repository maintainer
2. Do NOT: Create public GitHub issues for security vulnerabilities
3. Include: Detailed description, reproduction steps, and potential impact
4. Expect: Acknowledgment within 48 hours and status updates

• Authentication bypass vulnerabilities
• Data exposure or privacy violations
• Injection attacks (SQL, XSS, etc.)
• Rate limiting bypass
• Token or session management issues
• File upload vulnerabilities

• Issues requiring physical access to servers
• Social engineering attacks
• Denial of service attacks
• Issues in third-party dependencies (report to maintainers)

• Use Strong Secrets: Generate cryptographically secure keys
• Rotate Regularly: Change API keys and secrets periodically
• Separate Environments: Use different credentials for dev/staging/prod
• Secure Storage: Use Vercel's environment variable encryption

• API Key Protection: Secure Cloudflare D1 API keys
• Access Control: Limit database permissions to necessary operations
• Regular Backups: Implement automated database backups
• Monitoring: Monitor database access patterns

• HTTPS Only: Never deploy without TLS encryption
• Rate Limiting: Implement appropriate rate limits for your use case
• Input Validation: Validate all inputs before processing
• Authentication: Secure all admin endpoints with proper authentication

• Error Monitoring: Set up Sentry alerts for critical errors
• Performance Monitoring: Monitor function execution times
• Rate Limit Alerts: Alert on unusual rate limiting patterns
• Failed Authentication Alerts: Monitor for brute force attempts

• ✅ Background Processing: Secure token-based authentication implemented
• ✅ Privacy Audit: Zero transcript logging verified
• ✅ Input Validation: Comprehensive validation implemented
• ✅ Rate Limiting: Production-ready rate limiting active
• 🔄 Webhook Security: Mailgun HMAC signature verification pending

• Complete Webhook Signature Verification: Implement full Mailgun HMAC validation
• Advanced Rate Limiting: Redis-based distributed rate limiting
• Database Encryption: Implement field-level encryption for sensitive data
• Audit Logging: Enhanced audit trail for all user actions
• Security Scanning: Automated vulnerability scanning integration

• All environment variables configured with strong, unique values
• Google OAuth redirect URIs properly configured
• Mailgun webhook URLs use HTTPS
• Database API keys have minimal required permissions
• Admin email addresses verified and secure

• HTTPS certificate automatically provisioned
• Rate limiting functioning correctly
• Error monitoring active and configured
• Authentication flow tested
• Admin dashboard access verified

• Regular security updates applied
• Environment variables rotated quarterly
• Access logs reviewed monthly
• Error patterns monitored weekly
• Rate limiting effectiveness assessed monthly

# Generate a cryptographically secure secret
openssl rand -base64 32

# Use strong, unique values for all secrets
NEXTAUTH_SECRET=your-very-secure-random-32-character-secret
GOOGLE_CLIENT_SECRET=your-google-oauth-client-secret
D1_API_KEY=your-cloudflare-d1-api-key
MAILGUN_API_KEY=your-mailgun-api-key
OPENAI_API_KEY=your-openai-api-key

// Example rate limit configuration
const rateLimits = {
  webhook: { requests: 5, window: 60 }, // 5 requests per minute per user
  adminAPI: { requests: 30, window: 60 }, // 30 requests per minute per admin
  generalAPI: { requests: 100, window: 60 }, // 100 requests per minute per IP
  auth: { requests: 10, window: 900 } // 10 attempts per 15 minutes per IP
};

• OWASP Top 10: https://owasp.org/www-project-top-ten/
• Next.js Security: https://nextjs.org/docs/app/building-your-application/authentication
• Vercel Security: https://vercel.com/docs/security
• Cloudflare D1 Security: https://developers.cloudflare.com/d1/

For security-related questions or concerns, please contact the repository maintainers through appropriate channels. Do not post security issues publicly.

Last Updated: January 2025
Version: 1.0.0
Review Schedule: Quarterly security review and updates