1NAME 2 Authen::Captcha - Perl extension for creating captcha's to verify the 3 human element in transactions. 4 5SYNOPSIS 6 use Authen::Captcha; 7 8 # create a new object 9 my $captcha = Authen::Captcha->new(); 10 11 # set the data_folder. contains flatfile db to maintain state 12 $captcha->data_folder('/some/folder'); 13 14 # set directory to hold publicly accessable images 15 $captcha->output_folder('/some/http/folder'); 16 17 # Alternitively, any of the methods to set variables may also be 18 # used directly in the constructor 19 20 my $captcha = Authen::Captcha->new( 21 data_folder => '/some/folder', 22 output_folder => '/some/http/folder', 23 ); 24 25 # create a captcha. Image filename is "$md5sum.png" 26 my $md5sum = $captcha->generate_code($number_of_characters); 27 28 # check for a valid submitted captcha 29 # $code is the submitted letter combination guess from the user 30 # $md5sum is the submitted md5sum from the user (that we gave them) 31 my $results = $captcha->check_code($code,$md5sum); 32 # $results will be one of: 33 # 1 : Passed 34 # 0 : Code not checked (file error) 35 # -1 : Failed: code expired 36 # -2 : Failed: invalid code (not in database) 37 # -3 : Failed: invalid code (code does not match crypt) 38 ############## 39 40ABSTRACT 41 Authen::Captcha provides an object oriented interface to captcha file 42 creations. Captcha stands for Completely Automated Public Turning test 43 to tell Computers and Humans Apart. A Captcha is a program that can 44 generate and grade tests that: 45 46 - most humans can pass. 47 - current computer programs can't pass 48 49 The most common form is an image file containing distorted text, which 50 humans are adept at reading, and computers (generally) do a poor job. 51 This module currently implements that method. We plan to add other 52 methods, such as distorted sound files, and plain text riddles. 53 54REQUIRES 55 GD (see http://search.cpan.org/~lds/GD-2.11/) 56 Digest::MD5 (standard perl module) 57 58 In most common situations, you'll also want to have: 59 60 A web server (untested on windows, but it should work) 61 cgi-bin or mod-perl access 62 Perl: Perl 5.00503 or later must be installed on the web server. 63 GD.pm (with PNG support) 64 65INSTALLATION 66 Download the zipped tar file from: 67 68 http://search.cpan.org/search?dist=Authen-Captcha 69 70 Unzip the module as follows or use winzip: 71 72 tar -zxvf Authen-Captcha-1.xxx.tar.gz 73 74 The module can be installed using the standard Perl procedure: 75 76 perl Makefile.PL 77 make 78 make test 79 make install # you need to be root 80 81 Windows users without a working "make" can get nmake from: 82 83 ftp://ftp.microsoft.com/Softlib/MSLFILES/nmake15.exe 84 85METHODS 86 MAIN METHODS 87 88 "$captcha = Authen::Captcha->new();" 89 This creates a new Captcha object. Optionally, you can pass in a 90 hash with configuration information. See the method descriptions for 91 more detail on what they mean. 92 93 data_folder => '/some/folder', # required 94 output_folder => '/some/http/folder', # required 95 expire => 300, # optional. default 300 96 width => 25, # optional. default 25 97 height => 35, # optional. default 35 98 images_folder => '/some/folder', # optional. default to lib dir 99 debug => 0, # optional. default 0 100 101 "$md5sum = $captcha->generate_code( $number_of_characters );" 102 Creates a captcha. Image filename is "$md5sum.png" 103 104 It can also be called in array context to retrieve the string of 105 characters used to generate the captcha (the string the user is 106 expected to respond with). This is useful for debugging. ex. 107 108 "($md5sum,$chars) = $captcha->generate_code( $number_of_characters 109 );" 110 111 "$results = $captcha->check_code($code,$md5sum);" 112 check for a valid submitted captcha $code is the submitted letter 113 combination guess from the user $md5sum is the submitted md5sum from 114 the user (that we gave them) $results will be one of: 115 116 1 : Passed 117 0 : Code not checked (file error) 118 -1 : Failed: code expired 119 -2 : Failed: invalid code (not in database) 120 -3 : Failed: invalid code (code does not match crypt) 121 122 ACCESSOR METHODS 123 124 "$captcha->data_folder( '/some/folder' );" 125 Required. Sets the directory to hold the flatfile database that will 126 be used to store the current non-expired valid captcha md5sum's. 127 Must be writable by the process running the script (usually the web 128 server user, which is usually either "apache" or "http"), but should 129 not be accessable to the end user. 130 131 "$captcha->output_folder( '/some/folder' );" 132 Required. Sets the directory to hold the generated Captcha image 133 files. This is usually a web accessable directory so that the user 134 can view the images in here, but it doesn't have to be web 135 accessable (you could be attaching the images to an e-mail for some 136 verification, or some other Captcha implementation). Must be 137 writable by the process running the script (usually the web server 138 user, which is usually either "apache" or "http"). 139 140 "$captcha->images_folder( '/some/folder' );" 141 Optional, and may greatly affect the results... use with caution. 142 Allows you to override the default character graphic png's and 143 backgrounds with your own set of graphics. These are used in the 144 generation of the final captcha image file. The defaults are held 145 in: [lib install dir]/Authen/Captcha/images 146 147 "$captcha->expire( 300 );" 148 Optional. Sets the number of seconds this captcha will remain valid. 149 This means that the created captcha's will not remain valid forever, 150 just as long as you want them to be active. Set to an appropriate 151 value for your application. Defaults to 300. 152 153 "$captcha->width( 25 );" 154 Optional. Number of pixels high for the character graphics. Defaults 155 to 25. 156 157 "$captcha->height( 35 );" 158 Optional. Number of pixels wide for the character graphics. Defaults 159 to 35. 160 161 "$captcha->debug( [0|1|2] );" 162 Optional. Sets the debugging bit. 1 turns it on, 0 turns it off. 2 163 will print out verbose messages to STDERR. 164 165TODO 166 sound file captcha: Incorporating distorted sound file creation. 167 168SEE ALSO 169 The Captcha project: http://www.captcha.net/ 170 171 The origonal perl script this came from: 172 http://www.firstproductions.com/cgi/ 173 174AUTHORS 175 Seth T. Jackson, <sjackson@purifieddata.net> 176 177 Josh I. Miller, <jmiller@purifieddata.net> 178 179 First Productions, Inc. created the cgi-script distributed under the GPL 180 which was used as the basis for this module. Much work has gone into 181 making this more robust, and suitable for other applications, but much 182 of the origonal code remains. 183 184COPYRIGHT AND LICENSE 185 Copyright 2003, First Productions, Inc. (FIRSTPRODUCTIONS HUMAN TEST 186 1.0) 187 188 Copyright 2003 by Seth Jackson 189 190 This library is free software; you can redistribute it and/or modify it 191 under the terms of the GNU General Public License as published by the 192 Free Software Foundation; either version 2 of the License, or (at your 193 option) any later version. (see license.txt). 194 195 This program is distributed in the hope that it will be useful, but 196 WITHOUT ANY WARRANTY; without even the implied warranty of 197 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General 198 Public License for more details. 199 200 You should have received a copy of the GNU General Public License along 201 with this program; if not, write to the Free Software Foundation, Inc., 202 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 203 204