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<?php
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/*
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 * This is a PHP library that handles calling reCAPTCHA.
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 *    - Documentation and latest version
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 *          http://recaptcha.net/plugins/php/
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 *    - Get a reCAPTCHA API Key
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 *          https://www.google.com/recaptcha/admin/create
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 *    - Discussion group
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 *          http://groups.google.com/group/recaptcha
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 *
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 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
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 * AUTHORS:
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 *   Mike Crawford
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 *   Ben Maurer
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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 * THE SOFTWARE.
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 */
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/**
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 * The reCAPTCHA server URL's
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 */
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define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
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define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
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define("RECAPTCHA_VERIFY_SERVER", "www.google.com");
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/**
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 * Encodes the given data into a query string format
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 * @param $data - array of string elements to be encoded
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 * @return string - encoded request
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 */
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function _recaptcha_qsencode ($data) {
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        $req = "";
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        foreach ( $data as $key => $value )
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                $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
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        // Cut the last '&'
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        $req=substr($req,0,strlen($req)-1);
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        return $req;
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}
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/**
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 * Submits an HTTP POST to a reCAPTCHA server
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 * @param string $host
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 * @param string $path
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 * @param array $data
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 * @param int port
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 * @return array response
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 */
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function _recaptcha_http_post($host, $path, $data, $port = 80) {
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        $req = _recaptcha_qsencode ($data);
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        $http_request  = "POST $path HTTP/1.0\r\n";
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        $http_request .= "Host: $host\r\n";
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        $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
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        $http_request .= "Content-Length: " . strlen($req) . "\r\n";
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        $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
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        $http_request .= "\r\n";
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        $http_request .= $req;
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        $response = '';
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        if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
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                die ('Could not open socket');
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        }
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        fwrite($fs, $http_request);
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        while ( !feof($fs) )
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                $response .= fgets($fs, 1160); // One TCP-IP packet
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        fclose($fs);
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        $response = explode("\r\n\r\n", $response, 2);
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        return $response;
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}
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/**
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 * Gets the challenge HTML (javascript and non-javascript version).
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 * This is called from the browser, and the resulting reCAPTCHA HTML widget
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 * is embedded within the HTML form it was called from.
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 * @param string $pubkey A public key for reCAPTCHA
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 * @param string $error The error given by reCAPTCHA (optional, default is null)
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 * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
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 * @return string - The HTML to be embedded in the user's form.
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 */
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function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
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{
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        if ($pubkey == null || $pubkey == '') {
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                die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
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        }
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        if ($use_ssl) {
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                $server = RECAPTCHA_API_SECURE_SERVER;
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        } else {
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                $server = RECAPTCHA_API_SERVER;
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        }
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        $errorpart = "";
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        if ($error) {
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           $errorpart = "&amp;error=" . $error;
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        }
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        return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
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        <noscript>
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                <iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
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                <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
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                <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
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        </noscript>';
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}
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/**
135
 * A ReCaptchaResponse is returned from recaptcha_check_answer()
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 */
137
class ReCaptchaResponse {
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        var $is_valid;
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        var $error;
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}
141
 
142
 
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/**
144
  * Calls an HTTP POST function to verify if the user's guess was correct
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  * @param string $privkey
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  * @param string $remoteip
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  * @param string $challenge
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  * @param string $response
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  * @param array $extra_params an array of extra variables to post to the server
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  * @return ReCaptchaResponse
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  */
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function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
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{
154
        if ($privkey == null || $privkey == '') {
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                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>");
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        }
157
 
158
        if ($remoteip == null || $remoteip == '') {
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                die ("For security reasons, you must pass the remote ip to reCAPTCHA");
160
        }
161
 
162
 
163
 
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        //discard spam submissions
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        if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
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                $recaptcha_response = new ReCaptchaResponse();
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                $recaptcha_response->is_valid = false;
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                $recaptcha_response->error = 'incorrect-captcha-sol';
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                return $recaptcha_response;
170
        }
171
 
172
        $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
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                                          array (
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                                                 'privatekey' => $privkey,
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                                                 'remoteip' => $remoteip,
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                                                 'challenge' => $challenge,
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                                                 'response' => $response
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                                                 ) + $extra_params
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                                          );
180
 
181
        $answers = explode ("\n", $response [1]);
182
        $recaptcha_response = new ReCaptchaResponse();
183
 
184
        if (trim ($answers [0]) == 'true') {
185
                $recaptcha_response->is_valid = true;
186
        }
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        else {
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                $recaptcha_response->is_valid = false;
189
                $recaptcha_response->error = $answers [1];
190
        }
191
        return $recaptcha_response;
192
 
193
}
194
 
195
/**
196
 * gets a URL where the user can sign up for reCAPTCHA. If your application
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 * has a configuration page where you enter a key, you should provide a link
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 * using this function.
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 * @param string $domain The domain where the page is hosted
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 * @param string $appname The name of your application
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 */
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function recaptcha_get_signup_url ($domain = null, $appname = null) {
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        return "https://www.google.com/recaptcha/admin/create?" .  _recaptcha_qsencode (array ('domains' => $domain, 'app' => $appname));
204
}
205
 
206
function _recaptcha_aes_pad($val) {
207
        $block_size = 16;
208
        $numpad = $block_size - (strlen ($val) % $block_size);
209
        return str_pad($val, strlen ($val) + $numpad, chr($numpad));
210
}
211
 
212
/* Mailhide related code */
213
 
214
function _recaptcha_aes_encrypt($val,$ky) {
215
        if (! function_exists ("mcrypt_encrypt")) {
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                die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
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        }
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        $mode=MCRYPT_MODE_CBC;  
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        $enc=MCRYPT_RIJNDAEL_128;
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        $val=_recaptcha_aes_pad($val);
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        return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
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}
223
 
224
 
225
function _recaptcha_mailhide_urlbase64 ($x) {
226
        return strtr(base64_encode ($x), '+/', '-_');
227
}
228
 
229
/* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
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function recaptcha_mailhide_url($pubkey, $privkey, $email) {
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        if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
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                die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
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                     "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
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        }
235
 
236
 
237
        $ky = pack('H*', $privkey);
238
        $cryptmail = _recaptcha_aes_encrypt ($email, $ky);
239
 
240
        return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
241
}
242
 
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/**
244
 * gets the parts of the email to expose to the user.
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 * eg, given johndoe@example,com return ["john", "example.com"].
246
 * the email is then displayed as john...@example.com
247
 */
248
function _recaptcha_mailhide_email_parts ($email) {
249
        $arr = preg_split("/@/", $email );
250
 
251
        if (strlen ($arr[0]) <= 4) {
252
                $arr[0] = substr ($arr[0], 0, 1);
253
        } else if (strlen ($arr[0]) <= 6) {
254
                $arr[0] = substr ($arr[0], 0, 3);
255
        } else {
256
                $arr[0] = substr ($arr[0], 0, 4);
257
        }
258
        return $arr;
259
}
260
 
261
/**
262
 * Gets html to display an email address given a public an private key.
263
 * to get a key, go to:
264
 *
265
 * http://www.google.com/recaptcha/mailhide/apikey
266
 */
267
function recaptcha_mailhide_html($pubkey, $privkey, $email) {
268
        $emailparts = _recaptcha_mailhide_email_parts ($email);
269
        $url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
270
 
271
        return htmlentities($emailparts[0]) . "<a href='" . htmlentities ($url) .
272
                "' 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]);
273
 
274
}
275
 
276
 
277
?>