note 47650 deleted from ref.image by tularis
| From: | tularis@php.net | Date: | Sun, 29 Jun 2008 21:10:36 +0000 |
| Subject: | note 47650 deleted from ref.image by tularis | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-140965@lists.php.net to get a copy of this message | ||
Note Submitter: neo-maximus at blueyonder dot co dot uk
----
Create a user verification image like seen on sites like neopets. Now with encoded url image source
for extra security...
file : image.php
<?php
require_once "encode.php";
$decid = urldecode(md5_decrypt($_REQUEST['id'], $_REQUEST['key']));
header("Content-type: image/png");
$img = imagecreatetruecolor(65, 20);
$white = imagecolorallocate($img, 255, 255, 255);
$brown = imagecolorallocate($img, 255, 51, 51);
imagefill($img, 0, 0, $brown);
imagestring($img, 3, 6, 3, $decid, $white);
imagepng($img, '', 75);
imagedestroy($img);
?>
file : encode.php (with thanks to a post on md5 section)
<?php
function get_rnd_iv($iv_len){
$iv = '';
while ($iv_len-- > 0) {
$iv .= chr(mt_rand() & 0xff);
}
return $iv;
}
function md5_encrypt($plain_text, $password, $iv_len = 16){
$plain_text .= "\x13";
$n = strlen($plain_text);
if ($n % 16) $plain_text .= str_repeat("\0", 16 - ($n % 16));
$i = 0;
$enc_text = get_rnd_iv($iv_len);
$iv = substr($password ^ $enc_text, 0, 512);
while ($i < $n) {
$block = substr($plain_text, $i, 16) ^ pack('H*', md5($iv));
$enc_text .= $block;
$iv = substr($block . $iv, 0, 512) ^ $password;
$i += 16;
}
return base64_encode($enc_text);
}
function md5_decrypt($enc_text, $password, $iv_len = 16){
$enc_text = base64_decode($enc_text);
$n = strlen($enc_text);
$i = $iv_len;
$plain_text = '';
$iv = substr($password ^ substr($enc_text, 0, $iv_len), 0, 512);
while ($i < $n) {
$block = substr($enc_text, $i, 16);
$plain_text .= $block ^ pack('H*', md5($iv));
$iv = substr($block . $iv, 0, 512) ^ $password;
$i += 16;
}
return preg_replace('/\\x13\\x00*$/', '', $plain_text);
}
?>
file : webform.php
with this file simply do your webform as you normally would and simply include the image into the
file
i.e
<?php
require_once "encode.php";
$string = md5(rand(0, microtime()*1000000));
$verify_string = substr($string, 3, 7);
$key = md5(rand(0,999));
$encid = urlencode(md5_encrypt($verify_string, $key));
echo "<img src='1.php?id=$encid&key=$key'><br>";
echo "to verify the user would hve to type in $verify_string";
?>