Add User PII Encryption with Fernet Symmetric Encryption

ENCRYPTION_MIGRATION.md

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+# User Table Encryption Migration Guide
+
+This document explains the user table encryption implementation and production migration process.
+
+## Overview
+
+This implementation encrypts sensitive PII (Personally Identifiable Information) from the User table:
+- Email addresses
+- First names
+- Last names
+
+The encrypted data is stored in the Profile model using Fernet symmetric encryption (same encryption used for secure messaging in the platform).
+
+## Architecture
+
+### Components
+
+1. **Encrypted Field Classes** (`web/fields.py`)
+   - `EncryptedEmailField`: Encrypts email addresses
+   - `EncryptedCharField`: Encrypts character fields (first_name, last_name)
+   - `EncryptedTextField`: Encrypts longer text fields
+
+2. **Profile Model Extensions** (`web/models.py`)
+   - `encrypted_email`: Encrypted copy of user.email
+   - `encrypted_first_name`: Encrypted copy of user.first_name
+   - `encrypted_last_name`: Encrypted copy of user.last_name
+
+3. **Signal Handler** (`web/signals.py`)
+   - Automatically syncs encrypted fields when Profile is saved
+   - Keeps User and encrypted Profile fields in sync
+
+4. **Migrations**
+   - `0063_add_encrypted_user_fields.py`: Adds encrypted fields to Profile
+   - `0064_encrypt_existing_user_data.py`: Migrates existing data
+
+### How It Works
+
+1. Sensitive fields are stored encrypted in the Profile model
+2. The Profile model has a OneToOne relationship with User
+3. Custom field classes automatically encrypt/decrypt on save/load
+4. A signal keeps User and Profile fields synchronized
+5. Authentication continues to use the unencrypted username/password
+
+## Production Migration Steps
+
+### Prerequisites
+
+1. **Backup Database**
+   ```bash
+   # Example for MySQL
+   mysqldump -u username -p database_name > backup_$(date +%Y%m%d).sql
+   ```
+
+2. **Verify Encryption Key**
+   Ensure `MESSAGE_ENCRYPTION_KEY` is set in your `.env` file:
+   ```bash
+   grep MESSAGE_ENCRYPTION_KEY .env
+   ```
+   If not set, generate a new key:
+   ```bash
+   python web/master_key.py
+   ```
+
+3. **Test on Staging**
+   Always test the migration on a staging environment first.
+
+### Migration Process
+
+#### Step 1: Deploy Code
+
+Deploy the code changes to production:
+```bash
+git pull origin main
+# Restart your application server
+```
+
+#### Step 2: Run Migrations
+
+Apply the database migrations:
+```bash
+python manage.py migrate web
+```
+
+This will:
+- Add the three new encrypted fields to the Profile table
+- Run the data migration to encrypt existing user data
+
+#### Step 3: Verify Encryption
+
+Check that data was encrypted:
+```bash
+python scripts/migrate_encrypt_users.py
+```
+
+This script will:
+- Verify encryption key is configured
+- Check migrations are applied
+- Show statistics about encrypted records
+- Optionally re-encrypt any missed records
+
+#### Step 4: Test Application
+
+1. Test user login/authentication
+2. Test user profile viewing/editing
+3. Test signup flow
+4. Check that email notifications work
+5. Verify admin panel access
+
+### Alternative: Manual Migration Script
+
+If you prefer to run the encryption separately from the migration:
+
+```bash
+# Run migrations without data migration
+python manage.py migrate web 0063
+
+# Run the manual encryption script
+python scripts/migrate_encrypt_users.py
+
+# Then apply the data migration
+python manage.py migrate web 0064
+```
+
+## Rollback Procedure
+
+If you encounter issues, you can rollback:
+
+### Within 24 Hours (Data Still in User Table)
+
+```bash
+# Rollback migrations
+python manage.py migrate web 0062
+
+# Restart application
+sudo systemctl restart your-app-service
+```
+
+### After 24 Hours
+
+If you need to decrypt data back to User table:
+
+```python
+# In Django shell
+from web.models import Profile
+
+for profile in Profile.objects.all():
+    if profile.encrypted_email:
+        profile.user.email = profile.encrypted_email
+    if profile.encrypted_first_name:
+        profile.user.first_name = profile.encrypted_first_name
+    if profile.encrypted_last_name:
+        profile.user.last_name = profile.encrypted_last_name
+    profile.user.save()
+```
+
+Then rollback migrations as above.
+
+## Monitoring
+
+After migration, monitor for:
+
+1. **Authentication Issues**
+   - Users unable to login
+   - Password reset failures
+
+2. **Email Delivery**
+   - Notifications not sent
+   - Email addresses not resolved
+
+3. **Profile Display**
+   - Names not displaying correctly
+   - Profile edit failures
+
+## Security Considerations
+
+1. **Encryption Key Protection**
+   - Store `MESSAGE_ENCRYPTION_KEY` securely (environment variable)
+   - Never commit encryption key to version control
+   - Rotate key periodically (requires re-encryption)
+
+2. **Database Access**
+   - Encrypted data is only readable with the encryption key
+   - Direct database queries will show encrypted values
+
+3. **Backup Security**
+   - Database backups contain encrypted data
+   - Backups are useless without the encryption key
+   - Store backups and keys separately
+
+## Performance Impact
+
+- Minimal performance impact (< 1ms per operation)
+- Encryption happens on save, decryption on load
+- No impact on User authentication (username/password unchanged)
+
+## Troubleshooting
+
+### Decryption Errors
+
+If you see `[Error decrypting message]`:
+1. Check that MESSAGE_ENCRYPTION_KEY matches the key used for encryption
+2. Verify the key is properly formatted (base64 encoded)
+3. Check for data corruption in database
+
+### Migration Failures
+
+If migration fails:
+1. Check database permissions
+2. Verify all dependencies are installed
+3. Review migration logs for specific errors
+4. Rollback and retry with verbose logging:
+   ```bash
+   python manage.py migrate web --verbosity 2
+   ```
+
+### Signal Not Firing
+
+If encrypted fields aren't syncing:
+1. Check that `web.signals` is imported in `web/apps.py`
+2. Verify Profile signals are registered
+3. Check for transaction isolation issues
+
+## Support
+
+For issues or questions:
+1. Check application logs: `tail -f /var/log/your-app/error.log`
+2. Review Django logs for exceptions
+3. Contact development team
+
+## Changelog
+
+### Version 1.0 (Current)
+- Initial implementation of user table encryption
+- Added encrypted fields to Profile model
+- Created production migration scripts
+- Added automatic sync signals