Upgrading from reCAPTCHA v1 to v2 - server-side PHP - php

Question

I have a website that someone else has build. There is a register page that calls PHP which has the below:
require_once('inc/func/recaptchalib.php');
// Get a key from https://www.google.com/recaptcha/admin/create
$publickey = "XXXXXXX";
$privatekey = "XXXXXXX";
# The response from reCAPTCHA
$resp = null;
# The error code from reCAPTCHA, if any
$error = null;
# Was there a reCAPTCHA response?
if ($_POST["recaptcha_response_field"]) {
$resp = recaptcha_check_answer(
$privatekey,
$_SERVER["REMOTE_ADDR"],
$_POST["recaptcha_challenge_field"],
$_POST["recaptcha_response_field"]);
if ($resp->is_valid) {
//echo "You got it!";
}
else {
# Set the error code so that we can display it
//$error = $resp->error;
return "Invalid Verification Code (reenter CAPTCHA code)";
}
}
else {
return "Invalid Verification Code (reenter CAPTCHA code)";
}
As you can see the script is calling recaptchalib.php which is shown below:
<?php
/*
* This is a PHP library that handles calling reCAPTCHA.
* - Documentation and latest version
* http://recaptcha.net/plugins/php/
* - Get a reCAPTCHA API Key
* https://www.google.com/recaptcha/admin/create
* - Discussion group
* http://groups.google.com/group/recaptcha
*
* Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
* AUTHORS:
* Mike Crawford
* Ben Maurer
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
* The reCAPTCHA server URLs
*/
define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
define("RECAPTCHA_VERIFY_SERVER", "www.google.com");
/**
* Encodes the given data into a query string format
* #param $data - array of string elements to be encoded
* #return string - encoded request
*/
function _recaptcha_qsencode ($data) {
$req = "";
foreach ($data as $key => $value)
$req .= $key . '=' . urlencode(stripslashes($value)) . '&';
// Cut the last '&'
$req = substr($req, 0, strlen($req)-1);
return $req;
}
/**
* Submits an HTTP POST to a reCAPTCHA server
* #param string $host
* #param string $path
* #param array $data
* #param int port
* #return array response
*/
function _recaptcha_http_post($host, $path, $data, $port = 80) {
$req = _recaptcha_qsencode ($data);
$http_request = "POST $path HTTP/1.0\r\n";
$http_request .= "Host: $host\r\n";
$http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
$http_request .= "Content-Length: " . strlen($req) . "\r\n";
$http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
$http_request .= "\r\n";
$http_request .= $req;
$response = '';
if (false == ( $fs = #fsockopen($host, $port, $errno, $errstr, 10))) {
die ('Could not open socket');
}
fwrite($fs, $http_request);
while (!feof($fs))
$response .= fgets($fs, 1160); // One TCP-IP packet
fclose($fs);
$response = explode("\r\n\r\n", $response, 2);
return $response;
}
/**
* Gets the challenge HTML (JavaScript and non-JavaScript version).
* This is called from the browser, and the resulting reCAPTCHA HTML widget
* is embedded within the HTML form it was called from.
* #param string $pubkey A public key for reCAPTCHA
* #param string $error The error given by reCAPTCHA (optional, default is null)
* #param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
* #return string - The HTML to be embedded in the user's form.
*/
function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
{
if ($pubkey == null || $pubkey == '') {
die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
}
if ($use_ssl) {
$server = RECAPTCHA_API_SECURE_SERVER;
}
else {
$server = RECAPTCHA_API_SERVER;
}
$errorpart = "";
if ($error) {
$errorpart = "&error=" . $error;
}
return '<script type="text/javascript" src="'.
$server .
'/challenge?k=' .
$pubkey .
$errorpart .
'"></script>
<noscript>
<iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
<input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
</noscript>';
}
/**
* A ReCaptchaResponse is returned from recaptcha_check_answer()
*/
class ReCaptchaResponse {
var $is_valid;
var $error;
}
/**
* Calls an HTTP POST function to verify if the user's
* guess was correct
* #param string $privkey
* #param string $remoteip
* #param string $challenge
* #param string $response
* #param array $extra_params an array of extra variables
* to post to the server
* #return ReCaptchaResponse
*/
function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
{
if ($privkey == null || $privkey == '') {
die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
}
if ($remoteip == null || $remoteip == '') {
die ("For security reasons, you must pass the remote IP address to reCAPTCHA");
}
// Discard spam submissions
if ($challenge == null ||
strlen($challenge) == 0 ||
$response == null ||
strlen($response) == 0) {
$recaptcha_response = new ReCaptchaResponse();
$recaptcha_response->is_valid = false;
$recaptcha_response->error = 'incorrect-captcha-sol';
return $recaptcha_response;
}
$response = _recaptcha_http_post(
RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
array (
'privatekey' => $privkey,
'remoteip' => $remoteip,
'challenge' => $challenge,
'response' => $response
) + $extra_params
);
$answers = explode ("\n", $response [1]);
$recaptcha_response = new ReCaptchaResponse();
if (trim ($answers [0]) == 'true') {
$recaptcha_response->is_valid = true;
}
else {
$recaptcha_response->is_valid = false;
$recaptcha_response->error = $answers [1];
}
return $recaptcha_response;
}
/**
* Gets a URL where the user can sign up for reCAPTCHA. If your
* application has a configuration page where you enter a key,
* you should provide a link using this function.
* #param string $domain The domain where the page is hosted
* #param string $appname The name of your application
*/
function recaptcha_get_signup_url ($domain = null, $appname = null) {
return "https://www.google.com/recaptcha/admin/create?" .
_recaptcha_qsencode(array('domains' => $domain,
'app' => $appname));
}
function _recaptcha_aes_pad($val) {
$block_size = 16;
$numpad = $block_size - (strlen ($val) % $block_size);
return str_pad($val, strlen ($val) + $numpad, chr($numpad));
}
/* Mailhide-related code */
function _recaptcha_aes_encrypt($val, $ky) {
if (! function_exists ("mcrypt_encrypt")) {
die ("To use reCAPTCHA Mailhide, you need to have the mcrypt PHP module installed.");
}
$mode = MCRYPT_MODE_CBC;
$enc = MCRYPT_RIJNDAEL_128;
$val = _recaptcha_aes_pad($val);
return mcrypt_encrypt($enc,
$ky,
$val,
$mode,
"\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
}
function _recaptcha_mailhide_urlbase64 ($x) {
return strtr(base64_encode ($x), '+/', '-_');
}
/* Gets the reCAPTCHA Mailhide URL for a given email, public
key and private key */
function recaptcha_mailhide_url($pubkey, $privkey, $email) {
if ($pubkey == '' ||
$pubkey == null ||
$privkey == "" ||
$privkey == null) {
die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
"you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
}
$ky = pack('H*', $privkey);
$cryptmail = _recaptcha_aes_encrypt ($email, $ky);
return "http://www.google.com/recaptcha/mailhide/d?k=" .
$pubkey .
"&c=" .
_recaptcha_mailhide_urlbase64 ($cryptmail);
}
/**
* Gets the parts of the email to expose to the user.
* for example, given johndoe#example.com return ["john", "example.com"].
* the email is then displayed as john...#example.com
*/
function _recaptcha_mailhide_email_parts ($email) {
$arr = preg_split("/#/", $email);
if (strlen ($arr[0]) <= 4) {
$arr[0] = substr ($arr[0], 0, 1);
}
else if (strlen ($arr[0]) <= 6) {
$arr[0] = substr ($arr[0], 0, 3);
}
else {
$arr[0] = substr ($arr[0], 0, 4);
}
return $arr;
}
/**
* Gets HTML to display an email address given a public
* an private key. To get a key, go to:
*
* http://www.google.com/recaptcha/mailhide/apikey
*/
function recaptcha_mailhide_html($pubkey, $privkey, $email) {
$emailparts = _recaptcha_mailhide_email_parts ($email);
$url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
return htmlentities($emailparts[0]) .
"<a href='" . htmlentities ($url) .
"' onclick=\"window.open('" .
htmlentities ($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]);
}
?>
I need assistance upgrading this to V2. I want to do this via PHP if possible, but I am struggling to find out what I need to replace, etc.
How can I do this?