A simple PHP Verification Code program code

Verification code recognition is generally divided into the following steps:

1. Remove the font
2. Two-valued
3. Computational characteristics
4. Control Sample

The code is as follows

Copy Code

function _code ($_code_length = 4, $_width = +, $_height = 25) { For ($i =0 $i <$_code_length; $i + +) { $_nmsg. = Dechex (Mt_rand (0,15)); } $_session["code"] = $_nmsg; $_img = Imagecreatetruecolor ($_width, $_height); $_white = Imagecolorallocate ($_img, 250, 250, 250); Imagefill ($_img, 0, 0, $_white); $_gray = Imagecolorallocate ($_img, 196, 196, 196); Imagerectangle ($_img, 0, 0, $_width-1, $_height-1, $_gray); For ($i =0 $i < 6; $i + +) { $_md_color = Imagecolorallocate ($_img, Mt_rand (200,255), Mt_rand (200,255), Mt_rand (200,255)); Imageline ($_img, Mt_rand (0,$_width), Mt_rand (0, $_height), Mt_rand (0,$_width), Mt_rand (0, $_height), $_md_color); } for ($i =0; $i < $i + +) { $_md_color = Imagecolorallocate ($_img, Mt_rand (200,255), Mt_rand (200,255), Mt_rand (200,255)); Imagestring ($_img, 1, Mt_rand (1,$_width-5), Mt_rand (1, $_height-5), "*", $_md_color); } for ($i =0; $i < $_code_length; $i + +) { $_md_color = Imagecolorallocate ($_img, Mt_rand (0,102), Mt_rand (0,102), Mt_rand (0,102)); Imagestring ($_img, 5, $i * $_width/$_code_length+ Mt_rand (1), Mt_rand (1, $_HEIGHT/2), $_session["code" [$i], $_md_ color); } Header ("Content-type:image/png"); Imagepng ($_IMG); Imagedestroy ($_IMG); }

How to use validation code

code is as follows	copy code
$getcode = $_ post[' Code ']; If ($_session["code" = $getcode) {   echo ' validates legal, enters next ';   unset ($_session["Code"]); } Else {   echo ' Authentication code is incorrect ';   header (' location:vial.php '); }