HN CAPTCHA is a PHP class that generates a picture to use in forms that perform CAPTCHA tests (Completely Automated Public Turing to tell Computers from Humans Apart). After the test form is submitted, a key entered by the user in a text field is compared to determine whether it matches the text in the picture. It is a fork of ocr_captcha that features support for older versions of the GD library, hacking prevention, optional use of Web safe colors, support for the use of multiple random TrueType fonts, and more.
HN URL Rewrite can emulate page request URL rewriting and redirection. It can parse and change the output of the current page script to rewrite the URLs of links or images in the page with absolute URLs, relative URIs, and URLs that contain the scheme and host (http://www.somehost.com).
HN_htusers is a PHP class to manage users and groups in Apache Web server environments, with optional extra information for users. It uses Apache-style MD5-crypt passwords. It uses built-in CSS styles. Validation (min-max length, allowed characters) is built-in for all entries. The locking mechanism is robust. It includes examples of how to test your setup, how to embed a dynamic form for changing passwords into existing HTML code, using HTTP-Auth with .htaccess files in directories, and using HTTP-Auth without .htaccess files but with PHP.