1: <?php
  2: /*
  3:  * This is a PHP library that handles calling reCAPTCHA.
  4:  *    - Documentation and latest version
  5:  *          http://recaptcha.net/plugins/php/
  6:  *    - Get a reCAPTCHA API Key
  7:  *          https://www.google.com/recaptcha/admin/create
  8:  *    - Discussion group
  9:  *          http://groups.google.com/group/recaptcha
 10:  *
 11:  * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
 12:  * AUTHORS:
 13:  *   Mike Crawford
 14:  *   Ben Maurer
 15:  *
 16:  * Permission is hereby granted, free of charge, to any person obtaining a copy
 17:  * of this software and associated documentation files (the "Software"), to deal
 18:  * in the Software without restriction, including without limitation the rights
 19:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 20:  * copies of the Software, and to permit persons to whom the Software is
 21:  * furnished to do so, subject to the following conditions:
 22:  *
 23:  * The above copyright notice and this permission notice shall be included in
 24:  * all copies or substantial portions of the Software.
 25:  *
 26:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 27:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 28:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 29:  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 30:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 31:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 32:  * THE SOFTWARE.
 33:  */
 34: 
 35: /**
 36:  * The reCAPTCHA server URL's
 37:  */
 38: define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
 39: define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
 40: define("RECAPTCHA_VERIFY_SERVER", "www.google.com");
 41: 
 42: /**
 43:  * Encodes the given data into a query string format
 44:  * @param $data - array of string elements to be encoded
 45:  * @return string - encoded request
 46:  */
 47: function _recaptcha_qsencode ($data) {
 48:         $req = "";
 49:         foreach ( $data as $key => $value )
 50:                 $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
 51: 
 52:         // Cut the last '&'
 53:         $req=substr($req,0,strlen($req)-1);
 54:         return $req;
 55: }
 56: 
 57: 
 58: 
 59: /**
 60:  * Submits an HTTP POST to a reCAPTCHA server
 61:  * @param string $host
 62:  * @param string $path
 63:  * @param array $data
 64:  * @param int port
 65:  * @return array response
 66:  */
 67: function _recaptcha_http_post($host, $path, $data, $port = 80) {
 68: 
 69:         $req = _recaptcha_qsencode ($data);
 70: 
 71:         $http_request  = "POST $path HTTP/1.0\r\n";
 72:         $http_request .= "Host: $host\r\n";
 73:         $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
 74:         $http_request .= "Content-Length: " . strlen($req) . "\r\n";
 75:         $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
 76:         $http_request .= "\r\n";
 77:         $http_request .= $req;
 78: 
 79:         $response = '';
 80:         if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
 81:                 die ('Could not open socket');
 82:         }
 83: 
 84:         fwrite($fs, $http_request);
 85: 
 86:         while ( !feof($fs) )
 87:                 $response .= fgets($fs, 1160); // One TCP-IP packet
 88:         fclose($fs);
 89:         $response = explode("\r\n\r\n", $response, 2);
 90: 
 91:         return $response;
 92: }
 93: 
 94: 
 95: 
 96: /**
 97:  * Gets the challenge HTML (javascript and non-javascript version).
 98:  * This is called from the browser, and the resulting reCAPTCHA HTML widget
 99:  * is embedded within the HTML form it was called from.
100:  * @param string $pubkey A public key for reCAPTCHA
101:  * @param string $error The error given by reCAPTCHA (optional, default is null)
102:  * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
103: 
104:  * @return string - The HTML to be embedded in the user's form.
105:  */
106: function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
107: {
108:     if ($pubkey == null || $pubkey == '') {
109:         die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
110:     }
111: 
112:     if ($use_ssl) {
113:         $server = RECAPTCHA_API_SECURE_SERVER;
114:     } else {
115:         $server = RECAPTCHA_API_SERVER;
116:     }
117: 
118:     $errorpart = "";
119:     if ($error) {
120:         $errorpart = "&amp;error=" . $error;
121:     }
122:     return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
123:     <noscript>
124:         <iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" seamless="seamless"></iframe><br/>
125:         <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
126:         <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
127:     </noscript>';
128: }
129: 
130: 
131: 
132: 
133: /**
134:  * A ReCaptchaResponse is returned from recaptcha_check_answer()
135:  */
136: class ReCaptchaResponse {
137:         var $is_valid;
138:         var $error;
139: }
140: 
141: 
142: /**
143:   * Calls an HTTP POST function to verify if the user's guess was correct
144:   * @param string $privkey
145:   * @param string $remoteip
146:   * @param string $challenge
147:   * @param string $response
148:   * @param array $extra_params an array of extra variables to post to the server
149:   * @return ReCaptchaResponse
150:   */
151: function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
152: {
153:     if ($privkey == null || $privkey == '') {
154:         die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
155:     }
156: 
157:     if ($remoteip == null || $remoteip == '') {
158:         die ("For security reasons, you must pass the remote ip to reCAPTCHA");
159:     }
160: 
161: 
162: 
163:         //discard spam submissions
164:         if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
165:                 $recaptcha_response = new ReCaptchaResponse();
166:                 $recaptcha_response->is_valid = false;
167:                 $recaptcha_response->error = 'incorrect-captcha-sol';
168:                 return $recaptcha_response;
169:         }
170: 
171:         $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
172:                                           array (
173:                                                  'privatekey' => $privkey,
174:                                                  'remoteip' => $remoteip,
175:                                                  'challenge' => $challenge,
176:                                                  'response' => $response
177:                                                  ) + $extra_params
178:                                           );
179: 
180:         $answers = explode ("\n", $response [1]);
181:         $recaptcha_response = new ReCaptchaResponse();
182: 
183:         if (trim ($answers [0]) == 'true') {
184:                 $recaptcha_response->is_valid = true;
185:         }
186:         else {
187:                 $recaptcha_response->is_valid = false;
188:                 $recaptcha_response->error = $answers [1];
189:         }
190:         return $recaptcha_response;
191: 
192: }
193: 
194: /**
195:  * gets a URL where the user can sign up for reCAPTCHA. If your application
196:  * has a configuration page where you enter a key, you should provide a link
197:  * using this function.
198:  * @param string $domain The domain where the page is hosted
199:  * @param string $appname The name of your application
200:  */
201: function recaptcha_get_signup_url ($domain = null, $appname = null) {
202:     return "https://www.google.com/recaptcha/admin/create?" .  _recaptcha_qsencode (array ('domains' => $domain, 'app' => $appname));
203: }
204: 
205: function _recaptcha_aes_pad($val) {
206:     $block_size = 16;
207:     $numpad = $block_size - (strlen ($val) % $block_size);
208:     return str_pad($val, strlen ($val) + $numpad, chr($numpad));
209: }
210: 
211: /* Mailhide related code */
212: 
213: function _recaptcha_aes_encrypt($val,$ky) {
214:     if (! function_exists ("mcrypt_encrypt")) {
215:         die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
216:     }
217:     $mode=MCRYPT_MODE_CBC;
218:     $enc=MCRYPT_RIJNDAEL_128;
219:     $val=_recaptcha_aes_pad($val);
220:     return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
221: }
222: 
223: 
224: function _recaptcha_mailhide_urlbase64 ($x) {
225:     return strtr(base64_encode ($x), '+/', '-_');
226: }
227: 
228: /* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
229: function recaptcha_mailhide_url($pubkey, $privkey, $email) {
230:     if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
231:         die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
232:              "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
233:     }
234: 
235: 
236:     $ky = pack('H*', $privkey);
237:     $cryptmail = _recaptcha_aes_encrypt ($email, $ky);
238: 
239:     return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
240: }
241: 
242: /**
243:  * gets the parts of the email to expose to the user.
244:  * eg, given johndoe@example,com return ["john", "example.com"].
245:  * the email is then displayed as john...@example.com
246:  */
247: function _recaptcha_mailhide_email_parts ($email) {
248:     $arr = preg_split("/@/", $email );
249: 
250:     if (strlen ($arr[0]) <= 4) {
251:         $arr[0] = substr ($arr[0], 0, 1);
252:     } else if (strlen ($arr[0]) <= 6) {
253:         $arr[0] = substr ($arr[0], 0, 3);
254:     } else {
255:         $arr[0] = substr ($arr[0], 0, 4);
256:     }
257:     return $arr;
258: }
259: 
260: /**
261:  * Gets html to display an email address given a public an private key.
262:  * to get a key, go to:
263:  *
264:  * http://www.google.com/recaptcha/mailhide/apikey
265:  */
266: function recaptcha_mailhide_html($pubkey, $privkey, $email) {
267:     $emailparts = _recaptcha_mailhide_email_parts ($email);
268:     $url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
269: 
270:     return htmlentities($emailparts[0]) . "<a href='" . htmlentities ($url) .
271:         "' onclick=\"window.open('" . htmlentities ($url) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\">...</a>@" . htmlentities ($emailparts [1]);
272: 
273: }
274: 
275: 
276: ?>
277: