Create Complex Image Captcha

I’m upgrading my site’s security and need a self-hosted image captcha that shows highly obfuscated alphanumeric characters—no external services such as reCAPTCHA, just pure server-side generation. The captcha must be complex: random character rotation, varied fonts and colours, curved lines, background noise, even slight warping so automated solvers struggle while humans still read it.

Please build a small, clean module that I can drop into an existing PHP environment; if you prefer another language that runs easily on shared hosting, let me know. The code should let me set character length, timeout, and refresh behaviour from a simple config file.

Deliverables
• Source code with clear comments
• One-page integration guide and demo form
• Brief note on the libraries/extensions required and how to enable them

I’ll test by integrating the demo on my staging server: the captcha image must render in under 200 ms, reject incorrect entries, and pass a quick OCR attempt with a failure rate above 95 %. If that sounds straightforward, I’m ready to get started right away.