AJAX core library: possible breaking change, readystatechange functions are now called with the XHR instance as the first parameter, to allow requests to run in parallel. This means much better stability but may break some applets (compatibility hack is included)
<?php
/************************************************************\
*
* freeCap v1.4.1 Copyright 2005 Howard Yeend
* www.puremango.co.uk
*
* This file is part of freeCap.
*
* freeCap is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* freeCap is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with freeCap; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*
\************************************************************/
/**
* A port of the freeCap captcha engine to Enano.
*/
class captcha_engine_freecap extends captcha_base
{
var $site_tags = array();
var $tag_pos = 0;
var $rand_func = "mt_rand";
var $seed_func = "mt_srand";
var $hash_func = "sha1";
var $output = "png";
var $use_dict = false;
var $dict_location = "";
var $max_word_length = 7;
var $col_type = 1;
var $max_attempts = 20;
var $font_locations = Array();
var $bg_type = 3;
var $blur_bg = false;
var $bg_images = Array();
var $merge_type = 0;
var $morph_bg = true;
var $im, $im2, $im3;
var $font_size = 36;
var $debug = false;
function __construct($s, $r = false)
{
parent::__construct($s, $r);
// try to avoid the 'free p*rn' method of CAPTCHA circumvention
// see en.wikipedia.org/wiki/CAPTCHA for more info
// $this->site_tags[0] = "To avoid spam, please do NOT enter the text if";
// $this->site_tags[1] = "this site is not puremango.co.uk";
// or more simply:
// $site_tags[0] = "for use only on puremango.co.uk";
// reword or add lines as you please
// or if you don't want any text:
$this->site_tags = array();
// where to write the above:
// 0=top
// 1=bottom
// 2=both
$this->tag_pos = 1;
// functions to call for random number generation
// mt_rand produces 'better' random numbers
// but if your server doesn't support it, it's fine to use rand instead
$this->rand_func = "mt_rand";
$this->seed_func = "mt_srand";
// which type of hash to use?
// possible values: "sha1", "md5", "crc32"
// sha1 supported by PHP4.3.0+
// md5 supported by PHP3+
// crc32 supported by PHP4.0.1+
$this->hash_func = $this->session_fetch('hash_func', 'sha1');
// store in session so can validate in form processor
// image type:
// possible values: "jpg", "png", "gif"
// jpg doesn't support transparency (transparent bg option ends up white)
// png isn't supported by old browsers (see http://www.libpng.org/pub/png/pngstatus.html)
// gif may not be supported by your GD Lib.
$this->output = "png";
// 0=generate pseudo-random string, true=use dictionary
// dictionary is easier to recognise
// - both for humans and computers, so use random string if you're paranoid.
$this->use_dict = false;
// if your server is NOT set up to deny web access to files beginning ".ht"
// then you should ensure the dictionary file is kept outside the web directory
// eg: if www.foo.com/index.html points to c:\website\www\index.html
// then the dictionary should be placed in c:\website\dict.txt
// test your server's config by trying to access the dictionary through a web browser
// you should NOT be able to view the contents.
// can leave this blank if not using dictionary
$this->dict_location = ENANO_ROOT . "/includes/captcha/dicts/default.php";
// used to calculate image width, and for non-dictionary word generation
$this->max_word_length = 7;
// text colour
// 0=one random colour for all letters
// 1=different random colour for each letter
$this->col_type = 1;
// maximum times a user can refresh the image
// on a 6500 word dictionary, I think 15-50 is enough to not annoy users and make BF unfeasble.
// further notes re: BF attacks in "avoid brute force attacks" section, below
// on the other hand, those attempting OCR will find the ability to request new images
// very useful; if they can't crack one, just grab an easier target...
// for the ultra-paranoid, setting it to <5 will still work for most users
$this->max_attempts = 20;
// list of fonts to use
// font size should be around 35 pixels wide for each character.
// you can use my GD fontmaker script at www.puremango.co.uk to create your own fonts
// There are other programs to can create GD fonts, but my script allows a greater
// degree of control over exactly how wide each character is, and is therefore
// recommended for 'special' uses. For normal use of GD fonts,
// the GDFontGenerator @ http://www.philiplb.de is excellent for convering ttf to GD
// the fonts included with freeCap *only* include lowercase alphabetic characters
// so are not suitable for most other uses
// to increase security, you really should add other fonts
$this->font_locations = Array(
//ENANO_ROOT . "/includes/captcha/fonts/assimila.ttf",
//ENANO_ROOT . "/includes/captcha/fonts/elephant.ttf",
//ENANO_ROOT . "/includes/captcha/fonts/swash_normal.ttf",
//ENANO_ROOT . "/includes/captcha/fonts/.ttf",
//ENANO_ROOT . "/includes/captcha/fonts/trekker_regular.ttf"
ENANO_ROOT . "/includes/captcha/fonts/FreeMonoBold.ttf",
ENANO_ROOT . "/includes/captcha/fonts/FreeSerifBold.ttf",
ENANO_ROOT . "/includes/captcha/fonts/LiberationSans-Bold.ttf",
);
// background:
// 0=transparent (if jpg, white)
// 1=white bg with grid
// 2=white bg with squiggles
// 3=morphed image blocks
// 'random' background from v1.3 didn't provide any extra security (according to 2 independent experts)
// many thanks to http://ocr-research.org.ua and http://sam.zoy.org/pwntcha/ for testing
// for jpgs, 'transparent' is white
$this->bg_type = 3;
// should we blur the background? (looks nicer, makes text easier to read, takes longer)
$this->blur_bg = false;
// for bg_type 3, which images should we use?
// if you add your own, make sure they're fairly 'busy' images (ie a lot of shapes in them)
$this->bg_images = Array(
ENANO_ROOT . "/includes/captcha/pics/freecap_im1.jpg",
ENANO_ROOT . "/includes/captcha/pics/freecap_im2.jpg",
ENANO_ROOT . "/includes/captcha/pics/freecap_im3.jpg",
ENANO_ROOT . "/includes/captcha/pics/freecap_im4.jpg",
ENANO_ROOT . "/includes/captcha/pics/allyourbase.jpg"
);
// for non-transparent backgrounds only:
// if 0, merges CAPTCHA with bg
// if 1, write CAPTCHA over bg
$this->merge_type = 0;
// should we morph the bg? (recommend yes, but takes a little longer to compute)
$this->morph_bg = true;
// you shouldn't need to edit anything below this, but it's extensively commented if you do want to play
// have fun, and email me with ideas, or improvements to the code (very interested in speed improvements)
// hope this script saves some spam :-)
}
//////////////////////////////////////////////////////
////// Functions:
//////////////////////////////////////////////////////
function make_seed() {
// from http://php.net/srand
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((float) $usec * 100000);
}
function rand_color() {
$rf =& $this->rand_func;
if($this->bg_type==3)
{
// needs darker colour..
return $rf(10,100);
} else {
return $rf(60,170);
}
}
function myImageBlur($im)
{
// w00t. my very own blur function
// in GD2, there's a gaussian blur function. bunch of bloody show-offs... :-)
$width = imagesx($im);
$height = imagesy($im);
$temp_im = ImageCreateTrueColor($width,$height);
$bg = ImageColorAllocate($temp_im,150,150,150);
// preserves transparency if in orig image
ImageColorTransparent($temp_im,$bg);
// fill bg
ImageFill($temp_im,0,0,$bg);
// anything higher than 3 makes it totally unreadable
// might be useful in a 'real' blur function, though (ie blurring pictures not text)
$distance = 1;
// use $distance=30 to have multiple copies of the word. not sure if this is useful.
// blur by merging with itself at different x/y offsets:
ImageCopyMerge($temp_im, $im, 0, 0, 0, $distance, $width, $height-$distance, 70);
ImageCopyMerge($im, $temp_im, 0, 0, $distance, 0, $width-$distance, $height, 70);
ImageCopyMerge($temp_im, $im, 0, $distance, 0, 0, $width, $height, 70);
ImageCopyMerge($im, $temp_im, $distance, 0, 0, 0, $width, $height, 70);
// remove temp image
ImageDestroy($temp_im);
return $im;
}
function sendImage($pic)
{
// output image with appropriate headers
global $output,$im,$im2,$im3;
// ENANO - obfuscation technique disabled
// (this is for ethical reasons - ask dan at enanocms.org for information on why)
// Basically it outputs an X-Captcha header showing freeCap version, etc. Unnecessary
// header(base64_decode("WC1DYXB0Y2hhOiBmcmVlQ2FwIDEuNCAtIHd3dy5wdXJlbWFuZ28uY28udWs="));
if ( $this->debug )
{
$x = imagesx($pic) - 70;
$y = imagesy($pic) - 20;
$code = $this->get_code();
$red = ImageColorAllocateAlpha($pic, 0xAA, 0, 0, 72);
ImageString($pic, 5, $x, $y, $code, $red);
ImageString($pic, 5, 5, $y, "[debug mode]", $red);
}
switch($this->output)
{
// add other cases as desired
case "jpg":
header("Content-Type: image/jpeg");
ImageJPEG($pic);
break;
case "gif":
header("Content-Type: image/gif");
ImageGIF($pic);
break;
case "png":
default:
header("Content-Type: image/png");
ImagePNG($pic);
break;
}
// kill GD images (removes from memory)
ImageDestroy($this->im);
ImageDestroy($this->im2);
ImageDestroy($pic);
if(!empty($this->im3))
{
ImageDestroy($this->im3);
}
exit();
}
function make_image()
{
//////////////////////////////////////////////////////
////// Create Images + initialise a few things
//////////////////////////////////////////////////////
// seed random number generator
// PHP 4.2.0+ doesn't need this, but lower versions will
$this->seed_func($this->make_seed());
// how faded should the bg be? (100=totally gone, 0=bright as the day)
// to test how much protection the bg noise gives, take a screenshot of the freeCap image
// and take it into a photo editor. play with contrast and brightness.
// If you can remove most of the bg, then it's not a good enough percentage
switch($this->bg_type)
{
case 0:
break;
case 1:
case 2:
$bg_fade_pct = 65;
break;
case 3:
$bg_fade_pct = 50;
break;
}
// slightly randomise the bg fade
$bg_fade_pct += $this->rand_func(-2,2);
// read each font and get font character widths
// $font_widths = Array();
// for($i=0 ; $i<sizeof($this->font_locations) ; $i++)
// {
// $handle = fopen($this->font_locations[$i],"r");
// // read header of GD font, up to char width
// $c_wid = fread($handle,15);
// $font_widths[$i] = ord($c_wid{8})+ord($c_wid{9})+ord($c_wid{10})+ord($c_wid{11});
// fclose($handle);
// }
// modify image width depending on maximum possible length of word
// you shouldn't need to use words > 6 chars in length really.
$width = ($this->max_word_length*($this->font_size+10)+75);
$height = 90;
$this->im = ImageCreateTrueColor($width, $height);
$this->im2 = ImageCreateTrueColor($width, $height);
////////////////////////////////////////////////////////
// GENERATE IMAGE //
////////////////////////////////////////////////////////
$word = $this->get_code();
// save hash of word for comparison
// using hash so that if there's an insecurity elsewhere (eg on the form processor),
// an attacker could only get the hash
// also, shared servers usually give all users access to the session files
// echo `ls /tmp`; and echo `more /tmp/someone_elses_session_file`; usually work
// so even if your site is 100% secure, someone else's site on your server might not be
// hence, even if attackers can read the session file, they can't get the freeCap word
// (though most hashes are easy to brute force for simple strings)
//////////////////////////////////////////////////////
////// Fill BGs and Allocate Colours:
//////////////////////////////////////////////////////
// set tag colour
// have to do this before any distortion
// (otherwise colour allocation fails when bg type is 1)
$tag_col = ImageColorAllocate($this->im,10,10,10);
$site_tag_col2 = ImageColorAllocate($this->im2,0,0,0);
// set debug colours (text colours are set later)
$debug = ImageColorAllocate($this->im, 255, 0, 0);
$debug2 = ImageColorAllocate($this->im2, 255, 0, 0);
// set background colour (can change to any colour not in possible $text_col range)
// it doesn't matter as it'll be transparent or coloured over.
// if you're using bg_type 3, you might want to try to ensure that the color chosen
// below doesn't appear too much in any of your background images.
$bg = ImageColorAllocate($this->im, 254, 254, 254);
$bg2 = ImageColorAllocate($this->im2, 254, 254, 254);
// set transparencies
ImageColorTransparent($this->im,$bg);
// im2 transparent to allow characters to overlap slightly while morphing
ImageColorTransparent($this->im2,$bg2);
// fill backgrounds
ImageFill($this->im,0,0,$bg);
ImageFill($this->im2,0,0,$bg2);
if($this->bg_type!=0)
{
// generate noisy background, to be merged with CAPTCHA later
// any suggestions on how best to do this much appreciated
// sample code would be even better!
// I'm not an OCR expert (hell, I'm not even an image expert; puremango.co.uk was designed in MsPaint)
// so the noise models are based around my -guesswork- as to what would make it hard for an OCR prog
// ideally, the character obfuscation would be strong enough not to need additional background noise
// in any case, I hope at least one of the options given here provide some extra security!
$this->im3 = ImageCreateTrueColor($width,$height);
$temp_bg = ImageCreateTrueColor($width*1.5,$height*1.5);
$bg3 = ImageColorAllocate($this->im3,255,255,255);
ImageFill($this->im3,0,0,$bg3);
$temp_bg_col = ImageColorAllocate($temp_bg,255,255,255);
ImageFill($temp_bg,0,0,$temp_bg_col);
// we draw all noise onto temp_bg
// then if we're morphing, merge from temp_bg to im3
// or if not, just copy a $widthx$height portion of $temp_bg to $this->im3
// temp_bg is much larger so that when morphing, the edges retain the noise.
if($this->bg_type==1)
{
// grid bg:
// draw grid on x
for($i=$this->rand_func(6,20) ; $i<$width*2 ; $i+=$this->rand_func(10,25))
{
ImageSetThickness($temp_bg,$this->rand_func(2,6));
$text_r = $this->rand_func(100,150);
$text_g = $this->rand_func(100,150);
$text_b = $this->rand_func(100,150);
$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
ImageLine($temp_bg,$i,0,$i,$height*2,$text_colour3);
}
// draw grid on y
for($i=$this->rand_func(6,20) ; $i<$height*2 ; $i+=$this->rand_func(10,25))
{
ImageSetThickness($temp_bg,$this->rand_func(2,6));
$text_r = $this->rand_func(100,150);
$text_g = $this->rand_func(100,150);
$text_b = $this->rand_func(100,150);
$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
ImageLine($temp_bg,0,$i,$width*2, $i ,$text_colour3);
}
} else if($this->bg_type==2) {
// draw squiggles!
$bg3 = ImageColorAllocate($this->im3,255,255,255);
ImageFill($this->im3,0,0,$bg3);
ImageSetThickness($temp_bg,4);
for($i=0 ; $i<strlen($word)+1 ; $i++)
{
$text_r = $this->rand_func(100,150);
$text_g = $this->rand_func(100,150);
$text_b = $this->rand_func(100,150);
$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
$points = Array();
// draw random squiggle for each character
// the longer the loop, the more complex the squiggle
// keep random so OCR can't say "if found shape has 10 points, ignore it"
// each squiggle will, however, be a closed shape, so OCR could try to find
// line terminations and start from there. (I don't think they're that advanced yet..)
for($j=1 ; $j<$this->rand_func(5,10) ; $j++)
{
$points[] = $this->rand_func(1*(20*($i+1)),1*(50*($i+1)));
$points[] = $this->rand_func(30,$height+30);
}
ImagePolygon($temp_bg,$points,intval(sizeof($points)/2),$text_colour3);
}
} else if($this->bg_type==3) {
// take random chunks of $this->bg_images and paste them onto the background
for($i=0 ; $i<sizeof($this->bg_images) ; $i++)
{
// read each image and its size
$temp_im[$i] = ImageCreateFromJPEG($this->bg_images[$i]);
$temp_width[$i] = imagesx($temp_im[$i]);
$temp_height[$i] = imagesy($temp_im[$i]);
}
$blocksize = $this->rand_func(20,60);
for($i=0 ; $i<$width*2 ; $i+=$blocksize)
{
// could randomise blocksize here... hardly matters
for($j=0 ; $j<$height*2 ; $j+=$blocksize)
{
$this->image_index = $this->rand_func(0,sizeof($temp_im)-1);
$cut_x = $this->rand_func(0,$temp_width[$this->image_index]-$blocksize);
$cut_y = $this->rand_func(0,$temp_height[$this->image_index]-$blocksize);
ImageCopy($temp_bg, $temp_im[$this->image_index], $i, $j, $cut_x, $cut_y, $blocksize, $blocksize);
}
}
for($i=0 ; $i<sizeof($temp_im) ; $i++)
{
// remove bgs from memory
ImageDestroy($temp_im[$i]);
}
// for debug:
//sendImage($temp_bg);
}
// for debug:
//sendImage($this->im3);
if($this->morph_bg)
{
// morph background
// we do this separately to the main text morph because:
// a) the main text morph is done char-by-char, this is done across whole image
// b) if an attacker could un-morph the bg, it would un-morph the CAPTCHA
// hence bg is morphed differently to text
// why do we morph it at all? it might make it harder for an attacker to remove the background
// morph_chunk 1 looks better but takes longer
// this is a different and less perfect morph than the one we do on the CAPTCHA
// occasonally you get some dark background showing through around the edges
// it doesn't need to be perfect as it's only the bg.
$morph_chunk = $this->rand_func(1,5);
$morph_y = 0;
for($x=0 ; $x<$width ; $x+=$morph_chunk)
{
$morph_chunk = $this->rand_func(1,5);
$morph_y += $this->rand_func(-1,1);
ImageCopy($this->im3, $temp_bg, $x, 0, $x+30, 30+$morph_y, $morph_chunk, $height*2);
}
ImageCopy($temp_bg, $this->im3, 0, 0, 0, 0, $width, $height);
$morph_x = 0;
for($y=0 ; $y<=$height; $y+=$morph_chunk)
{
$morph_chunk = $this->rand_func(1,5);
$morph_x += $this->rand_func(-1,1);
ImageCopy($this->im3, $temp_bg, $morph_x, $y, 0, $y, $width, $morph_chunk);
}
} else {
// just copy temp_bg onto im3
ImageCopy($this->im3,$temp_bg,0,0,30,30,$width,$height);
}
ImageDestroy($temp_bg);
if($this->blur_bg)
{
$this->myImageBlur($this->im3);
}
}
// for debug:
//sendImage($this->im3);
//////////////////////////////////////////////////////
////// Write Word
//////////////////////////////////////////////////////
// write word in random starting X position
$word_start_x = $this->rand_func(5,32);
// y positions jiggled about later
$word_start_y = 50;
// use last pixelwidth
$font_pixelwidth = $this->font_size + 10;
if($this->col_type==0)
{
$text_r = $this->rand_color();
$text_g = $this->rand_color();
$text_b = $this->rand_color();
$text_colour2 = ImageColorAllocate($this->im2, $text_r, $text_g, $text_b);
}
// write each char in different font
for($i=0 ; $i<strlen($word) ; $i++)
{
if($this->col_type==1)
{
$text_r = $this->rand_color();
$text_g = $this->rand_color();
$text_b = $this->rand_color();
$text_colour2 = ImageColorAllocate($this->im2, $text_r, $text_g, $text_b);
}
$j = $this->rand_func(0,sizeof($this->font_locations)-1);
// $font = ImageLoadFont($this->font_locations[$j]);
// ImageString($this->im2, $font, $word_start_x+($font_widths[$j]*$i), $word_start_y, $word{$i}, $text_colour2);
ImageTTFText($this->im2, $this->font_size, 0, $word_start_x+(($font_pixelwidth)*$i), $word_start_y, $text_colour2, $this->font_locations[$j], $word{$i});
}
// for debug:
// $this->sendImage($this->im2);
//////////////////////////////////////////////////////
////// Morph Image:
//////////////////////////////////////////////////////
// calculate how big the text is in pixels
// (so we only morph what we need to)
$word_pix_size = $word_start_x+(strlen($word)*$font_pixelwidth);
// firstly move each character up or down a bit:
$y_pos = 0;
for($i=$word_start_x ; $i<$word_pix_size ; $i+=$font_pixelwidth)
{
// move on Y axis
// deviates at least 4 pixels between each letter
$prev_y = $y_pos;
do{
$y_pos = $this->rand_func(-5,5);
} while($y_pos<$prev_y+2 && $y_pos>$prev_y-2);
ImageCopy($this->im, $this->im2, $i, $y_pos, $i, 0, $font_pixelwidth, $height);
// for debug:
// ImageRectangle($this->im,$i,$y_pos+10,$i+$font_pixelwidth,$y_pos+70,$debug);
}
// for debug:
// $this->sendImage($this->im);
ImageFilledRectangle($this->im2,0,0,$width,$height,$bg2);
// randomly morph each character individually on x-axis
// this is where the main distortion happens
// massively improved since v1.2
$y_chunk = 1;
$morph_factor = 1;
$morph_x = 0;
for($j=0 ; $j<strlen($word) ; $j++)
{
$y_pos = 0;
for($i=0 ; $i<=$height; $i+=$y_chunk)
{
$orig_x = $word_start_x+($j*$font_pixelwidth);
// morph x += so that instead of deviating from orig x each time, we deviate from where we last deviated to
// get it? instead of a zig zag, we get more of a sine wave.
// I wish we could deviate more but it looks crap if we do.
$morph_x += $this->rand_func(-$morph_factor,$morph_factor);
// had to change this to ImageCopyMerge when starting using ImageCreateTrueColor
// according to the manual; "when (pct is) 100 this function behaves identically to imagecopy()"
// but this is NOT true when dealing with transparencies...
ImageCopyMerge($this->im2, $this->im, $orig_x+$morph_x, $i+$y_pos, $orig_x, $i, $font_pixelwidth, $y_chunk, 100);
// for debug:
//ImageLine($this->im2, $orig_x+$morph_x, $i, $orig_x+$morph_x+1, $i+$y_chunk, $debug2);
//ImageLine($this->im2, $orig_x+$morph_x+$font_pixelwidth, $i, $orig_x+$morph_x+$font_pixelwidth+1, $i+$y_chunk, $debug2);
}
}
// for debug:
//sendImage($this->im2);
ImageFilledRectangle($this->im,0,0,$width,$height,$bg);
// now do the same on the y-axis
// (much easier because we can just do it across the whole image, don't have to do it char-by-char)
$y_pos = 0;
$x_chunk = 1;
for($i=0 ; $i<=$width ; $i+=$x_chunk)
{
// can result in image going too far off on Y-axis;
// not much I can do about that, apart from make image bigger
// again, I wish I could do 1.5 pixels
$y_pos += $this->rand_func(-1,1);
ImageCopy($this->im, $this->im2, $i, $y_pos, $i, 0, $x_chunk, $height);
// for debug:
//ImageLine($this->im,$i+$x_chunk,0,$i+$x_chunk,100,$debug);
//ImageLine($this->im,$i,$y_pos+25,$i+$x_chunk,$y_pos+25,$debug);
}
// for debug:
//sendImage($this->im);
// blur edges:
// doesn't really add any security, but looks a lot nicer, and renders text a little easier to read
// for humans (hopefully not for OCRs, but if you know better, feel free to disable this function)
// (and if you do, let me know why)
$this->myImageBlur($this->im);
// for debug:
//sendImage($this->im);
if($this->output!="jpg" && $this->bg_type==0)
{
// make background transparent
ImageColorTransparent($this->im,$bg);
}
//////////////////////////////////////////////////////
////// Try to avoid 'free p*rn' style CAPTCHA re-use
//////////////////////////////////////////////////////
// ('*'ed to stop my site coming up for certain keyword searches on google)
// can obscure CAPTCHA word in some cases..
// write site tags 'shining through' the morphed image
ImageFilledRectangle($this->im2,0,0,$width,$height,$bg2);
if(is_array($this->site_tags))
{
for($i=0 ; $i<sizeof($this->site_tags) ; $i++)
{
// ensure tags are centered
$tag_width = strlen($this->site_tags[$i])*6;
// write tag is chosen position
if($this->tag_pos==0 || $this->tag_pos==2)
{
// write at top
ImageString($this->im2, 2, intval($width/2)-intval($tag_width/2), (10*$i), $this->site_tags[$i], $site_tag_col2);
}
if($this->tag_pos==1 || $this->tag_pos==2)
{
// write at bottom
ImageString($this->im2, 2, intval($width/2)-intval($tag_width/2), ($height-34+($i*10)), $this->site_tags[$i], $site_tag_col2);
}
}
}
ImageCopyMerge($this->im2,$this->im,0,0,0,0,$width,$height,80);
ImageCopy($this->im,$this->im2,0,0,0,0,$width,$height);
// for debug:
//sendImage($this->im);
//////////////////////////////////////////////////////
////// Merge with obfuscated background
//////////////////////////////////////////////////////
if($this->bg_type!=0)
{
// merge bg image with CAPTCHA image to create smooth background
// fade bg:
if($this->bg_type!=3)
{
$temp_im = ImageCreateTrueColor($width,$height);
$white = ImageColorAllocate($temp_im,255,255,255);
ImageFill($temp_im,0,0,$white);
ImageCopyMerge($this->im3,$temp_im,0,0,0,0,$width,$height,$bg_fade_pct);
// for debug:
//sendImage($this->im3);
ImageDestroy($temp_im);
$c_fade_pct = 50;
} else {
$c_fade_pct = $bg_fade_pct;
}
// captcha over bg:
// might want to not blur if using this method
// otherwise leaves white-ish border around each letter
if($this->merge_type==1)
{
ImageCopyMerge($this->im3,$this->im,0,0,0,0,$width,$height,100);
ImageCopy($this->im,$this->im3,0,0,0,0,$width,$height);
} else {
// bg over captcha:
ImageCopyMerge($this->im,$this->im3,0,0,0,0,$width,$height,$c_fade_pct);
}
}
// for debug:
//sendImage($this->im);
//////////////////////////////////////////////////////
////// Write tags, remove variables and output!
//////////////////////////////////////////////////////
// tag it
// feel free to remove/change
// but if it's not essential I'd appreciate you leaving it
// after all, I've put a lot of work into this and am giving it away for free
// the least you could do is give me credit (or buy me stuff from amazon!)
// but I understand that in professional environments, your boss might not like this tag
// so that's cool.
$tag_str = "";
// for debug:
//$tag_str = "[".$word."]";
// ensure tag is right-aligned
$tag_width = strlen($tag_str)*6;
// write tag
ImageString($this->im, 2, $width-$tag_width, $height-13, $tag_str, $tag_col);
// unset all sensetive vars
// in case someone include()s this file on a shared server
// you might think this unneccessary, as it exit()s
// but by using register_shutdown_function
// on a -very- insecure shared server, they -might- be able to get the word
unset($word);
// the below aren't really essential, but might aid an OCR attack if discovered.
// so we unset them
// output final image :-)
$this->sendImage($this->im);
// (sendImage also destroys all used images)
}
function rand_func($s, $m)
{
global $_starttime;
$tn = microtime_float() - $_starttime;
if ( $tn > 5 )
{
echo '<pre>';
enano_debug_print_backtrace();
echo '</pre>';
exit;
}
$rf =& $this->rand_func;
return $rf($s, $m);
}
function seed_func($s)
{
$rf =& $this->seed_func;
return $rf($s);
}
function hash_func($s)
{
$rf =& $this->hash_func;
return $rf($s);
}
}