+ − <?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);
+ − }
+ −
+ − }