817 lines
26 KiB
PHP
817 lines
26 KiB
PHP
<?
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/************************************************************\
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*
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* freeCap v1.4.1 Copyright 2005 Howard Yeend
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* www.puremango.co.uk
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*
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* This file is part of freeCap.
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*
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* freeCap is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* freeCap is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with freeCap; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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\************************************************************/
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session_start();
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//////////////////////////////////////////////////////
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////// User Defined Vars:
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//////////////////////////////////////////////////////
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// try to avoid the 'free p*rn' method of CAPTCHA circumvention
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// see www.wikipedia.com/captcha for more info
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$site_tags[0] = "To avoid spam, please do NOT enter the text if";
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$site_tags[1] = "this site is not puremango.co.uk";
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// or more simply:
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//$site_tags[0] = "for use only on puremango.co.uk";
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// reword or add lines as you please
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// or if you don't want any text:
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$site_tags = null;
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// where to write the above:
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// 0=top
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// 1=bottom
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// 2=both
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$tag_pos = 1;
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// functions to call for random number generation
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// mt_rand produces 'better' random numbers
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// but if your server doesn't support it, it's fine to use rand instead
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$rand_func = "mt_rand";
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$seed_func = "mt_srand";
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// which type of hash to use?
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// possible values: "sha1", "md5", "crc32"
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// sha1 supported by PHP4.3.0+
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// md5 supported by PHP3+
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// crc32 supported by PHP4.0.1+
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$hash_func = "sha1";
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// store in session so can validate in form processor
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$_SESSION['hash_func'] = $hash_func;
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// image type:
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// possible values: "jpg", "png", "gif"
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// jpg doesn't support transparency (transparent bg option ends up white)
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// png isn't supported by old browsers (see http://www.libpng.org/pub/png/pngstatus.html)
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// gif may not be supported by your GD Lib.
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$output = "png";
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// 0=generate pseudo-random string, 1=use dictionary
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// dictionary is easier to recognise
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// - both for humans and computers, so use random string if you're paranoid.
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$use_dict = 1;
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// if your server is NOT set up to deny web access to files beginning ".ht"
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// then you should ensure the dictionary file is kept outside the web directory
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// eg: if www.foo.com/index.html points to c:\website\www\index.html
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// then the dictionary should be placed in c:\website\dict.txt
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// test your server's config by trying to access the dictionary through a web browser
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// you should NOT be able to view the contents.
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// can leave this blank if not using dictionary
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$dict_location = "./.ht_freecap_words";
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// used to calculate image width, and for non-dictionary word generation
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$max_word_length = 6;
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// text colour
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// 0=one random colour for all letters
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// 1=different random colour for each letter
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$col_type = 1;
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// maximum times a user can refresh the image
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// on a 6500 word dictionary, I think 15-50 is enough to not annoy users and make BF unfeasble.
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// further notes re: BF attacks in "avoid brute force attacks" section, below
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// on the other hand, those attempting OCR will find the ability to request new images
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// very useful; if they can't crack one, just grab an easier target...
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// for the ultra-paranoid, setting it to <5 will still work for most users
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$max_attempts = 20;
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// list of fonts to use
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// font size should be around 35 pixels wide for each character.
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// you can use my GD fontmaker script at www.puremango.co.uk to create your own fonts
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// There are other programs to can create GD fonts, but my script allows a greater
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// degree of control over exactly how wide each character is, and is therefore
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// recommended for 'special' uses. For normal use of GD fonts,
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// the GDFontGenerator @ http://www.philiplb.de is excellent for convering ttf to GD
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// the fonts included with freeCap *only* include lowercase alphabetic characters
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// so are not suitable for most other uses
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// to increase security, you really should add other fonts
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$font_locations = Array("./.ht_freecap_font1.gdf","./.ht_freecap_font2.gdf","./.ht_freecap_font3.gdf","./.ht_freecap_font4.gdf","./.ht_freecap_font5.gdf");
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// background:
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// 0=transparent (if jpg, white)
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// 1=white bg with grid
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// 2=white bg with squiggles
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// 3=morphed image blocks
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// 'random' background from v1.3 didn't provide any extra security (according to 2 independent experts)
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// many thanks to http://ocr-research.org.ua and http://sam.zoy.org/pwntcha/ for testing
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// for jpgs, 'transparent' is white
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$bg_type = 2;
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// should we blur the background? (looks nicer, makes text easier to read, takes longer)
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$blur_bg = false;
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// for bg_type 3, which images should we use?
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// if you add your own, make sure they're fairly 'busy' images (ie a lot of shapes in them)
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$bg_images = Array("./.ht_freecap_im1.jpg","./.ht_freecap_im2.jpg","./.ht_freecap_im3.jpg","./.ht_freecap_im4.jpg","./.ht_freecap_im5.jpg");
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// for non-transparent backgrounds only:
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// if 0, merges CAPTCHA with bg
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// if 1, write CAPTCHA over bg
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$merge_type = 0;
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// should we morph the bg? (recommend yes, but takes a little longer to compute)
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$morph_bg = true;
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// you shouldn't need to edit anything below this, but it's extensively commented if you do want to play
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// have fun, and email me with ideas, or improvements to the code (very interested in speed improvements)
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// hope this script saves some spam :-)
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//////////////////////////////////////////////////////
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////// Create Images + initialise a few things
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//////////////////////////////////////////////////////
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// seed random number generator
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// PHP 4.2.0+ doesn't need this, but lower versions will
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$seed_func(make_seed());
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// how faded should the bg be? (100=totally gone, 0=bright as the day)
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// to test how much protection the bg noise gives, take a screenshot of the freeCap image
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// and take it into a photo editor. play with contrast and brightness.
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// If you can remove most of the bg, then it's not a good enough percentage
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switch($bg_type)
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{
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case 0:
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break;
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case 1:
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case 2:
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$bg_fade_pct = 65;
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break;
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case 3:
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$bg_fade_pct = 50;
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break;
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}
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// slightly randomise the bg fade
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$bg_fade_pct += $rand_func(-2,2);
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// read each font and get font character widths
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$font_widths = Array();
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for($i=0 ; $i<sizeof($font_locations) ; $i++)
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{
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$handle = fopen($font_locations[$i],"r");
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// read header of GD font, up to char width
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$c_wid = fread($handle,11);
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$font_widths[$i] = ord($c_wid{8})+ord($c_wid{9})+ord($c_wid{10})+ord($c_wid{11});
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fclose($handle);
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}
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// modify image width depending on maximum possible length of word
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// you shouldn't need to use words > 6 chars in length really.
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$width = ($max_word_length*(array_sum($font_widths)/sizeof($font_widths))+75);
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$height = 90;
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$im = ImageCreate($width, $height);
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$im2 = ImageCreate($width, $height);
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//////////////////////////////////////////////////////
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////// Avoid Brute Force Attacks:
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//////////////////////////////////////////////////////
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if(empty($_SESSION['freecap_attempts']))
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{
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$_SESSION['freecap_attempts'] = 1;
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} else {
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$_SESSION['freecap_attempts']++;
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// if more than ($max_attempts) refreshes, block further refreshes
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// can be negated by connecting with new session id
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// could get round this by storing num attempts in database against IP
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// could get round that by connecting with different IP (eg, using proxy servers)
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// in short, there's little point trying to avoid brute forcing
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// the best way to protect against BF attacks is to ensure the dictionary is not
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// accessible via the web or use random string option
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if($_SESSION['freecap_attempts']>$max_attempts)
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{
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$_SESSION['freecap_word_hash'] = false;
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$bg = ImageColorAllocate($im,255,255,255);
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ImageColorTransparent($im,$bg);
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$red = ImageColorAllocate($im, 255, 0, 0);
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// depending on how rude you want to be :-)
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//ImageString($im,5,0,20,"bugger off you spamming bastards!",$red);
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ImageString($im,5,15,20,"service no longer available",$red);
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sendImage($im);
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}
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}
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//////////////////////////////////////////////////////
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////// Functions:
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//////////////////////////////////////////////////////
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function make_seed() {
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// from http://php.net/srand
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list($usec, $sec) = explode(' ', microtime());
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return (float) $sec + ((float) $usec * 100000);
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}
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function rand_color() {
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global $bg_type,$rand_func;
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if($bg_type==3)
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{
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// needs darker colour..
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return $rand_func(10,100);
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} else {
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return $rand_func(60,170);
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}
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}
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function myImageBlur($im)
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{
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// w00t. my very own blur function
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// in GD2, there's a gaussian blur function. bunch of bloody show-offs... :-)
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$width = imagesx($im);
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$height = imagesy($im);
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$temp_im = ImageCreateTrueColor($width,$height);
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$bg = ImageColorAllocate($temp_im,150,150,150);
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// preserves transparency if in orig image
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ImageColorTransparent($temp_im,$bg);
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// fill bg
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ImageFill($temp_im,0,0,$bg);
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// anything higher than 3 makes it totally unreadable
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// might be useful in a 'real' blur function, though (ie blurring pictures not text)
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$distance = 1;
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// use $distance=30 to have multiple copies of the word. not sure if this is useful.
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// blur by merging with itself at different x/y offsets:
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ImageCopyMerge($temp_im, $im, 0, 0, 0, $distance, $width, $height-$distance, 70);
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ImageCopyMerge($im, $temp_im, 0, 0, $distance, 0, $width-$distance, $height, 70);
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ImageCopyMerge($temp_im, $im, 0, $distance, 0, 0, $width, $height, 70);
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ImageCopyMerge($im, $temp_im, $distance, 0, 0, 0, $width, $height, 70);
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// remove temp image
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ImageDestroy($temp_im);
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return $im;
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}
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function sendImage($pic)
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{
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// output image with appropriate headers
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global $output,$im,$im2,$im3;
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header(base64_decode("WC1DYXB0Y2hhOiBmcmVlQ2FwIDEuNCAtIHd3dy5wdXJlbWFuZ28uY28udWs="));
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switch($output)
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{
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// add other cases as desired
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case "jpg":
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header("Content-Type: image/jpeg");
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ImageJPEG($pic);
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break;
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case "gif":
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header("Content-Type: image/gif");
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ImageGIF($pic);
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break;
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case "png":
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default:
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header("Content-Type: image/png");
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ImagePNG($pic);
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break;
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}
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// kill GD images (removes from memory)
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ImageDestroy($im);
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ImageDestroy($im2);
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ImageDestroy($pic);
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if(!empty($im3))
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{
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ImageDestroy($im3);
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}
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exit();
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}
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//////////////////////////////////////////////////////
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////// Choose Word:
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//////////////////////////////////////////////////////
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if($use_dict==1)
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{
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// load dictionary and choose random word
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$words = @file($dict_location);
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$word = strtolower($words[$rand_func(0,sizeof($words)-1)]);
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// cut off line endings/other possible odd chars
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$word = preg_replace('/[^a-z]/', '',$word);
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// might be large file so forget it now (frees memory)
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$words = "";
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unset($words);
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} else {
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// based on code originally by breakzero at hotmail dot com
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// (http://uk.php.net/manual/en/function.rand.php)
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// generate pseudo-random string
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// doesn't use ijtf as are easily mistaken
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// I'm not using numbers because the custom fonts I've created don't support anything other than
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// lowercase or space (but you can download new fonts or create your own using my GD fontmaker script)
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$consonants = 'bcdghklmnpqrsvwxyz';
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$vowels = 'aeuo';
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$word = "";
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$wordlen = $rand_func(5,$max_word_length);
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for($i=0 ; $i<$wordlen ; $i++)
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{
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// don't allow to start with 'vowel'
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if($rand_func(0,4)>=2 && $i!=0)
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{
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$word .= $vowels{$rand_func(0,strlen($vowels)-1)};
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} else {
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$word .= $consonants{$rand_func(0,strlen($consonants)-1)};
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}
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}
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}
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// save hash of word for comparison
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// using hash so that if there's an insecurity elsewhere (eg on the form processor),
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// an attacker could only get the hash
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// also, shared servers usually give all users access to the session files
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// echo `ls /tmp`; and echo `more /tmp/someone_elses_session_file`; usually work
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// so even if your site is 100% secure, someone else's site on your server might not be
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// hence, even if attackers can read the session file, they can't get the freeCap word
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// (though most hashes are easy to brute force for simple strings)
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$_SESSION['freecap_word_hash'] = $hash_func($word);
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//////////////////////////////////////////////////////
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////// Fill BGs and Allocate Colours:
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//////////////////////////////////////////////////////
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// set tag colour
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// have to do this before any distortion
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// (otherwise colour allocation fails when bg type is 1)
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$tag_col = ImageColorAllocate($im,10,10,10);
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$site_tag_col2 = ImageColorAllocate($im2,0,0,0);
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// set debug colours (text colours are set later)
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$debug = ImageColorAllocate($im, 255, 0, 0);
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$debug2 = ImageColorAllocate($im2, 255, 0, 0);
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// set background colour (can change to any colour not in possible $text_col range)
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// it doesn't matter as it'll be transparent or coloured over.
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// if you're using bg_type 3, you might want to try to ensure that the color chosen
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// below doesn't appear too much in any of your background images.
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$bg = ImageColorAllocate($im, 254, 254, 254);
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$bg2 = ImageColorAllocate($im2, 254, 254, 254);
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// set transparencies
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ImageColorTransparent($im,$bg);
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// im2 transparent to allow characters to overlap slightly while morphing
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ImageColorTransparent($im2,$bg2);
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// fill backgrounds
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ImageFill($im,0,0,$bg);
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ImageFill($im2,0,0,$bg2);
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if($bg_type!=0)
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{
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// generate noisy background, to be merged with CAPTCHA later
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// any suggestions on how best to do this much appreciated
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// sample code would be even better!
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// I'm not an OCR expert (hell, I'm not even an image expert; puremango.co.uk was designed in MsPaint)
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// so the noise models are based around my -guesswork- as to what would make it hard for an OCR prog
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// ideally, the character obfuscation would be strong enough not to need additional background noise
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// in any case, I hope at least one of the options given here provide some extra security!
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$im3 = ImageCreateTrueColor($width,$height);
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$temp_bg = ImageCreateTrueColor($width*1.5,$height*1.5);
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$bg3 = ImageColorAllocate($im3,255,255,255);
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ImageFill($im3,0,0,$bg3);
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$temp_bg_col = ImageColorAllocate($temp_bg,255,255,255);
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ImageFill($temp_bg,0,0,$temp_bg_col);
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// we draw all noise onto temp_bg
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// then if we're morphing, merge from temp_bg to im3
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// or if not, just copy a $widthx$height portion of $temp_bg to $im3
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// temp_bg is much larger so that when morphing, the edges retain the noise.
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if($bg_type==1)
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{
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// grid bg:
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// draw grid on x
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for($i=$rand_func(6,20) ; $i<$width*2 ; $i+=$rand_func(10,25))
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{
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ImageSetThickness($temp_bg,$rand_func(2,6));
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$text_r = $rand_func(100,150);
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$text_g = $rand_func(100,150);
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$text_b = $rand_func(100,150);
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$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
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ImageLine($temp_bg,$i,0,$i,$height*2,$text_colour3);
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}
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// draw grid on y
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for($i=$rand_func(6,20) ; $i<$height*2 ; $i+=$rand_func(10,25))
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{
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ImageSetThickness($temp_bg,$rand_func(2,6));
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$text_r = $rand_func(100,150);
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$text_g = $rand_func(100,150);
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$text_b = $rand_func(100,150);
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$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
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ImageLine($temp_bg,0,$i,$width*2, $i ,$text_colour3);
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}
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} else if($bg_type==2) {
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// draw squiggles!
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$bg3 = ImageColorAllocate($im3,255,255,255);
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ImageFill($im3,0,0,$bg3);
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ImageSetThickness($temp_bg,4);
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for($i=0 ; $i<strlen($word)+1 ; $i++)
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{
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$text_r = $rand_func(100,150);
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$text_g = $rand_func(100,150);
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$text_b = $rand_func(100,150);
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$text_colour3 = ImageColorAllocate($temp_bg, $text_r, $text_g, $text_b);
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$points = Array();
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// draw random squiggle for each character
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// the longer the loop, the more complex the squiggle
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// keep random so OCR can't say "if found shape has 10 points, ignore it"
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// each squiggle will, however, be a closed shape, so OCR could try to find
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// line terminations and start from there. (I don't think they're that advanced yet..)
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for($j=1 ; $j<$rand_func(5,10) ; $j++)
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{
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$points[] = $rand_func(1*(20*($i+1)),1*(50*($i+1)));
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$points[] = $rand_func(30,$height+30);
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}
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ImagePolygon($temp_bg,$points,intval(sizeof($points)/2),$text_colour3);
|
|
}
|
|
|
|
} else if($bg_type==3) {
|
|
// take random chunks of $bg_images and paste them onto the background
|
|
|
|
for($i=0 ; $i<sizeof($bg_images) ; $i++)
|
|
{
|
|
// read each image and its size
|
|
$temp_im[$i] = ImageCreateFromJPEG($bg_images[$i]);
|
|
$temp_width[$i] = imagesx($temp_im[$i]);
|
|
$temp_height[$i] = imagesy($temp_im[$i]);
|
|
}
|
|
|
|
$blocksize = $rand_func(20,60);
|
|
for($i=0 ; $i<$width*2 ; $i+=$blocksize)
|
|
{
|
|
// could randomise blocksize here... hardly matters
|
|
for($j=0 ; $j<$height*2 ; $j+=$blocksize)
|
|
{
|
|
$image_index = $rand_func(0,sizeof($temp_im)-1);
|
|
$cut_x = $rand_func(0,$temp_width[$image_index]-$blocksize);
|
|
$cut_y = $rand_func(0,$temp_height[$image_index]-$blocksize);
|
|
ImageCopy($temp_bg, $temp_im[$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($im3);
|
|
|
|
if($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 = $rand_func(1,5);
|
|
$morph_y = 0;
|
|
for($x=0 ; $x<$width ; $x+=$morph_chunk)
|
|
{
|
|
$morph_chunk = $rand_func(1,5);
|
|
$morph_y += $rand_func(-1,1);
|
|
ImageCopy($im3, $temp_bg, $x, 0, $x+30, 30+$morph_y, $morph_chunk, $height*2);
|
|
}
|
|
|
|
ImageCopy($temp_bg, $im3, 0, 0, 0, 0, $width, $height);
|
|
|
|
$morph_x = 0;
|
|
for($y=0 ; $y<=$height; $y+=$morph_chunk)
|
|
{
|
|
$morph_chunk = $rand_func(1,5);
|
|
$morph_x += $rand_func(-1,1);
|
|
ImageCopy($im3, $temp_bg, $morph_x, $y, 0, $y, $width, $morph_chunk);
|
|
|
|
}
|
|
} else {
|
|
// just copy temp_bg onto im3
|
|
ImageCopy($im3,$temp_bg,0,0,30,30,$width,$height);
|
|
}
|
|
|
|
ImageDestroy($temp_bg);
|
|
|
|
if($blur_bg)
|
|
{
|
|
myImageBlur($im3);
|
|
}
|
|
}
|
|
// for debug:
|
|
//sendImage($im3);
|
|
|
|
|
|
|
|
|
|
//////////////////////////////////////////////////////
|
|
////// Write Word
|
|
//////////////////////////////////////////////////////
|
|
|
|
// write word in random starting X position
|
|
$word_start_x = $rand_func(5,32);
|
|
// y positions jiggled about later
|
|
$word_start_y = 15;
|
|
|
|
if($col_type==0)
|
|
{
|
|
$text_r = rand_color();
|
|
$text_g = rand_color();
|
|
$text_b = rand_color();
|
|
$text_colour2 = ImageColorAllocate($im2, $text_r, $text_g, $text_b);
|
|
}
|
|
|
|
// write each char in different font
|
|
for($i=0 ; $i<strlen($word) ; $i++)
|
|
{
|
|
if($col_type==1)
|
|
{
|
|
$text_r = rand_color();
|
|
$text_g = rand_color();
|
|
$text_b = rand_color();
|
|
$text_colour2 = ImageColorAllocate($im2, $text_r, $text_g, $text_b);
|
|
}
|
|
|
|
$j = $rand_func(0,sizeof($font_locations)-1);
|
|
$font = ImageLoadFont($font_locations[$j]);
|
|
ImageString($im2, $font, $word_start_x+($font_widths[$j]*$i), $word_start_y, $word{$i}, $text_colour2);
|
|
}
|
|
// use last pixelwidth
|
|
$font_pixelwidth = $font_widths[$j];
|
|
|
|
// for debug:
|
|
//sendImage($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)*$font_pixelwidth);
|
|
|
|
// firstly move each character up or down a bit:
|
|
for($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 = $rand_func(-5,5);
|
|
} while($y_pos<$prev_y+2 && $y_pos>$prev_y-2);
|
|
ImageCopy($im, $im2, $i, $y_pos, $i, 0, $font_pixelwidth, $height);
|
|
|
|
// for debug:
|
|
//ImageRectangle($im,$i,$y_pos+10,$i+$font_pixelwidth,$y_pos+70,$debug);
|
|
}
|
|
|
|
// for debug:
|
|
//sendImage($im);
|
|
|
|
ImageFilledRectangle($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 += $rand_func(-$morph_factor,$morph_factor);
|
|
// had to change this to ImageCopyMerge when starting using ImageCreateTrueColor
|
|
// according to the manual; "when (pct is) 100 this function behaves identically to imagecopy()"
|
|
// but this is NOT true when dealing with transparencies...
|
|
ImageCopyMerge($im2, $im, $orig_x+$morph_x, $i+$y_pos, $orig_x, $i, $font_pixelwidth, $y_chunk, 100);
|
|
|
|
// for debug:
|
|
//ImageLine($im2, $orig_x+$morph_x, $i, $orig_x+$morph_x+1, $i+$y_chunk, $debug2);
|
|
//ImageLine($im2, $orig_x+$morph_x+$font_pixelwidth, $i, $orig_x+$morph_x+$font_pixelwidth+1, $i+$y_chunk, $debug2);
|
|
}
|
|
}
|
|
|
|
// for debug:
|
|
//sendImage($im2);
|
|
|
|
ImageFilledRectangle($im,0,0,$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 += $rand_func(-1,1);
|
|
ImageCopy($im, $im2, $i, $y_pos, $i, 0, $x_chunk, $height);
|
|
|
|
// for debug:
|
|
//ImageLine($im,$i+$x_chunk,0,$i+$x_chunk,100,$debug);
|
|
//ImageLine($im,$i,$y_pos+25,$i+$x_chunk,$y_pos+25,$debug);
|
|
}
|
|
|
|
// for debug:
|
|
//sendImage($im);
|
|
|
|
// blur edges:
|
|
// doesn't really add any security, but looks a lot nicer, and renders text a little easier to read
|
|
// for humans (hopefully not for OCRs, but if you know better, feel free to disable this function)
|
|
// (and if you do, let me know why)
|
|
myImageBlur($im);
|
|
|
|
// for debug:
|
|
//sendImage($im);
|
|
|
|
if($output!="jpg" && $bg_type==0)
|
|
{
|
|
// make background transparent
|
|
ImageColorTransparent($im,$bg);
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
//////////////////////////////////////////////////////
|
|
////// Try to avoid 'free p*rn' style CAPTCHA re-use
|
|
//////////////////////////////////////////////////////
|
|
// ('*'ed to stop my site coming up for certain keyword searches on google)
|
|
|
|
// can obscure CAPTCHA word in some cases..
|
|
|
|
// write site tags 'shining through' the morphed image
|
|
ImageFilledRectangle($im2,0,0,$width,$height,$bg2);
|
|
if(is_array($site_tags))
|
|
{
|
|
for($i=0 ; $i<sizeof($site_tags) ; $i++)
|
|
{
|
|
// ensure tags are centered
|
|
$tag_width = strlen($site_tags[$i])*6;
|
|
// write tag is chosen position
|
|
if($tag_pos==0 || $tag_pos==2)
|
|
{
|
|
// write at top
|
|
ImageString($im2, 2, intval($width/2)-intval($tag_width/2), (10*$i), $site_tags[$i], $site_tag_col2);
|
|
}
|
|
if($tag_pos==1 || $tag_pos==2)
|
|
{
|
|
// write at bottom
|
|
ImageString($im2, 2, intval($width/2)-intval($tag_width/2), ($height-34+($i*10)), $site_tags[$i], $site_tag_col2);
|
|
}
|
|
}
|
|
}
|
|
ImageCopyMerge($im2,$im,0,0,0,0,$width,$height,80);
|
|
ImageCopy($im,$im2,0,0,0,0,$width,$height);
|
|
// for debug:
|
|
//sendImage($im);
|
|
|
|
|
|
|
|
|
|
//////////////////////////////////////////////////////
|
|
////// Merge with obfuscated background
|
|
//////////////////////////////////////////////////////
|
|
|
|
if($bg_type!=0)
|
|
{
|
|
// merge bg image with CAPTCHA image to create smooth background
|
|
|
|
// fade bg:
|
|
if($bg_type!=3)
|
|
{
|
|
$temp_im = ImageCreateTrueColor($width,$height);
|
|
$white = ImageColorAllocate($temp_im,255,255,255);
|
|
ImageFill($temp_im,0,0,$white);
|
|
ImageCopyMerge($im3,$temp_im,0,0,0,0,$width,$height,$bg_fade_pct);
|
|
// for debug:
|
|
//sendImage($im3);
|
|
ImageDestroy($temp_im);
|
|
$c_fade_pct = 50;
|
|
} else {
|
|
$c_fade_pct = $bg_fade_pct;
|
|
}
|
|
|
|
// captcha over bg:
|
|
// might want to not blur if using this method
|
|
// otherwise leaves white-ish border around each letter
|
|
if($merge_type==1)
|
|
{
|
|
ImageCopyMerge($im3,$im,0,0,0,0,$width,$height,100);
|
|
ImageCopy($im,$im3,0,0,0,0,$width,$height);
|
|
} else {
|
|
// bg over captcha:
|
|
ImageCopyMerge($im,$im3,0,0,0,0,$width,$height,$c_fade_pct);
|
|
}
|
|
}
|
|
// for debug:
|
|
//sendImage($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.
|
|
$tag_str = "freeCap v1.41 - puremango.co.uk";
|
|
// for debug:
|
|
//$tag_str = "[".$word."]";
|
|
|
|
// ensure tag is right-aligned
|
|
$tag_width = strlen($tag_str)*6;
|
|
// write tag
|
|
ImageString($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
|
|
unset($use_dict);
|
|
unset($dict_location);
|
|
unset($max_word_length);
|
|
unset($bg_type);
|
|
unset($bg_images);
|
|
unset($merge_type);
|
|
unset($bg_fade_pct);
|
|
unset($morph_bg);
|
|
unset($col_type);
|
|
unset($max_attempts);
|
|
unset($font_locations);
|
|
|
|
|
|
// output final image :-)
|
|
sendImage($im);
|
|
// (sendImage also destroys all used images)
|
|
?>
|