Protection from Automated Access by SpamBots, Turing Test using PHP Verification

• Antispamify forms or protect files (ie. mailto: links) from bots
• Use your own form, or our simple built-in form
• Attempts to verify requests are coming from a human at 3 levels:
  • captcha code verified by a human
  • shared form secret that must be posted
  • timelimit between requesting the form and submission
• Can also provide simple password protection for applications
• Is now cookie independent because we need to dynamically change session id (FireFox image caching)
• $_SESSION is used to store: 1) form start time, 2) shared form secret, 3) md5 hashed verify_code
• session id passed to v_image in a URL, that can't inadvertently be shared by the user
• Includes embedded data validation for the posted verification data
• dynamic input borders dependent on access to jquery for an IE hack

Howto:

• Create PHP files from source code for v_image.php, v_require.php, and optionally v_form.php, and make php files in a web folder
• or Download the zipped PHP files and unzip into in a web folder
• Then add these to the page to protect (requirer) above the doctype declaration
  • optional over-rides, add these vars in the requirer to over-ride defaults:
  • $login_required = FALSE; // can be set in the requirer if this script called from more than one other page
  • $form_needed = FALSE; // defaults to TRUE
  • these 2 req'd minimum, set and add these lines in the requirer above your doctype declaration:
  • $v_dir = ""; // relative path from this to the v_file's folder (without trailing "/")
  • require_once($v_dir."/v_require.php"); // below the $v_dir var but early in a requirer page needing verification
• Adjust these "user vars" at the top of v_require.php as needed
  • $debug = FALSE;
  • $js_dir = "/pathto/jquery.js"; // dynamic input borders for IE less than 7
  • $v_username = "admin"; // set this if auth required (case-sensitive)
  • $v_password = "4magic"; // set this if auth required (case-sensitive)
• Add/Adjust any/all of these "user vars" to your requirer page to over-ride the defaults in v_require
  • $vCodeLen = 3; // over-ride the default of a 3 character verification code
  • $timeLimit = 60; // over-ride the form's default lifetime of 60 seconds to submit
  • $v_img_color_bg = "fff"; // over-ride the default of fff, use either 3 or 6 character hex color codes
  • $v_img_color_txt = "888"; // over-ride the default of 888, use either 3 or 6 character hex color codes
  • $v_img_width = 100; // over-ride the default px width of the captcha image
  • $v_img_height = 19; // over-ride the default px height of the captcha image
• If using your own form, add the following local style to the head of your form page to get the captcha

•       <style type="text/css" media="all"><!--
          @import "your/forms.css";
          #verify_code { background: url('/v_image.php?') white 50% 0% no-repeat; }
        //-->
        </style>

• and the following form inputs:
  • <form id="" class="" action="<?php echo $_SERVER['PHP_SELF'] ?>" method="post">
  • <input type="text" name="verify_code" id="verify_code" />
  • <input type="hidden" name="secret" value="" />
  • <input type="hidden" name="" value="" />
  • if using v_image.php as src for an image, rather than a css background, the above inputs must appear after <img src="v_image.php" ...