Prompt

Harden API security against common attacks.

<api_structure>
{API endpoints and methods}
</api_structure>

<authentication>
{current auth mechanism}
</authentication>

<sensitive_data>
{data types handled}
</sensitive_data>

Harden:
1. Authentication strengthening
2. Input validation rules
3. Output encoding
4. CORS configuration
5. Security headers
6. Audit logging