Security Implementation Guide

ChatFuse implements comprehensive cookie security measures:

Authentication Cookies (Essential)

• Name: session_token (or __Host-session_token in production)
• Security Flags: HttpOnly, Secure, SameSite=Lax
• Implementation: HMAC-SHA256 hashed session IDs
• Expiry: Rolling (24 hours) and absolute (30 days)
• Data: Opaque session IDs only (no PII)

UI Preferences Cookies (Functional)

• Purpose: Non-sensitive user interface state
• Examples: Newsletter subscription, persona greetings, demo tokens
• Storage: Cookie-based UI preferences API
• Security: No sensitive data, proper categorization

CSRF Protection Cookies (Security)

• Purpose: Cross-Site Request Forgery protection
• Implementation: Double-submit pattern with synchronizer tokens
• Expiry: Short-lived (30 minutes)
• Validation: HMAC signature verification

Staging Gate Cookies (Security)

• Purpose: Staging environment access control
• Implementation: HMAC-signed, opaque values
• Expiry: Short-lived (30 minutes)
• Security: No PII or user data

HMAC-SHA256 Token Hashing

• Algorithm: HMAC-SHA256 with environment secrets
• Storage: Only hashed tokens in database
• Verification: Cryptographic signature validation
• Rotation: Automatic on privilege changes

Multi-Device Support

• Features: List all active sessions
• Management: Revoke individual or all sessions
• Anomaly Detection: IP and User-Agent tracking
• Notifications: Security event logging

Rolling & Absolute Expiry

• Rolling Expiry: 24 hours of inactivity (configurable)
• Absolute Expiry: 30 days maximum (configurable)
• Activity Tracking: Automatic refresh on usage
• Cleanup: Background job purges expired sessions

PKCE Implementation

• Standard: RFC 7636 Proof Key for Code Exchange
• Code Challenge: SHA256 hash of code verifier
• Code Verifier: Cryptographically random string
• Storage: Temporary server-side storage with TTL

State Management

• HMAC Signatures: Cryptographically signed state parameters
• TTL Validation: 10-minute expiry for OAuth states
• Provider Isolation: Separate state per OAuth provider
• Redirect Validation: Secure redirect URL handling

Session Rotation

• Automatic: Session invalidation on OAuth login
• Security: Prevents session fixation attacks
• Logging: Security event tracking for OAuth flows

Content Security Policy (CSP)

• Default Source: Strict 'self' policy
• Script Sources: Controlled inline scripts and eval
• Style Sources: Self and inline styles
• Image Sources: Self and data URLs
• Connect Sources: Self, WebSocket, and HTTPS

Additional Headers

• X-Content-Type-Options: nosniff
• Referrer-Policy: strict-origin-when-cross-origin
• Permissions-Policy: Restrictive feature permissions
• Strict-Transport-Security: HSTS in production

OpenTelemetry Integration

• Replacement: Replaces Sentry for error reporting
• Structured Logging: JSON-formatted logs with metadata
• Security Events: Authentication, session, and anomaly logging
• PII Sanitization: Automatic sensitive data filtering

GCP Error Reporting

• Integration: Cloud-based error aggregation
• Context: Request context and user information
• Privacy: PII sanitization before transmission
• Alerting: Automated security event notifications

Data Categorization

• Essential Cookies: Required for service functionality
• Functional Cookies: UI preferences and settings
• Security Cookies: CSRF protection and staging access
• Analytics: Server-side only (no client-side tracking)

User Rights

• Access: View all stored data
• Portability: Download personal data
• Deletion: Remove all personal data
• Correction: Update personal information

Retention Policies

• Session Data: 30 days maximum
• Audit Logs: 90 days for security events
• User Data: Until account deletion
• Error Logs: 30 days with PII sanitization

• XSS Protection: HttpOnly cookies prevent script access
• CSRF Protection: Double-submit tokens and origin validation
• Session Security: HMAC hashing and anomaly detection
• OAuth Security: PKCE and state parameter validation

• Data Minimization: Only necessary data in cookies
• User Control: Comprehensive privacy dashboard
• Transparency: Clear cookie categorization
• Compliance: GDPR/CCPA ready implementation

• Reduced Payload: Smaller, focused cookies
• Better Caching: Optimized cookie management
• Faster Load Times: Efficient session handling
• Improved UX: Seamless authentication flows

1. 100% localStorage/sessionStorage elimination
2. Enterprise-grade cookie security implementation
3. HMAC-SHA256 session token hashing
4. CSRF protection with double-submit pattern
5. OAuth security with PKCE implementation
6. Security headers with strict CSP policies
7. OpenTelemetry + GCP Error Reporting
8. Comprehensive privacy compliance

• Frontend Audit: 0 localStorage/sessionStorage violations
• Backend Tests: All security features operational
• Integration Tests: Comprehensive security coverage
• Compliance Review: GDPR/CCPA requirements met