Python Security Best Practices

Review and secure my Python application:

Application type: [WEB/API/CLI/SERVICE]
Framework: [DJANGO/FLASK/FASTAPI/NONE]

Security areas to address:
- [ ] Input validation
- [ ] SQL injection
- [ ] XSS prevention
- [ ] CSRF protection
- [ ] Authentication
- [ ] Authorization
- [ ] Secret management
- [ ] Dependency vulnerabilities
- [ ] File upload security
- [ ] Logging sensitive data

Current code (optional):
```python
[PASTE CODE FOR REVIEW]
```

Provide:
1. Security checklist
2. Input validation patterns
3. Parameterized queries
4. Password hashing (bcrypt/argon2)
5. JWT handling
6. HTTPS enforcement
7. Security headers
8. Dependency scanning (safety, bandit)
9. Secret management
10. Security testing