Experimentally changing how content-length works.
<?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);
}
}