From 376d78392451f3e4aae8b98377b33409d02ff8d2 Mon Sep 17 00:00:00 2001
From: Marcel Werk <burntime@woltlab.com>
Date: Mon, 20 May 2013 22:18:35 +0200
Subject: [PATCH] Merged com.woltlab.wcf.recaptcha into WCF

---
 com.woltlab.wcf/option.xml                    |  28 +++
 com.woltlab.wcf/template/recaptcha.tpl        |  55 ++++++
 .../files/lib/form/RecaptchaForm.class.php    |  96 ++++++++++
 .../recaptcha/RecaptchaHandler.class.php      | 180 ++++++++++++++++++
 wcfsetup/install/files/style/recaptcha.less   |   5 +
 wcfsetup/install/lang/de.xml                  |  25 ++-
 wcfsetup/install/lang/en.xml                  |  25 ++-
 7 files changed, 396 insertions(+), 18 deletions(-)
 create mode 100644 com.woltlab.wcf/template/recaptcha.tpl
 create mode 100644 wcfsetup/install/files/lib/form/RecaptchaForm.class.php
 create mode 100644 wcfsetup/install/files/lib/system/recaptcha/RecaptchaHandler.class.php
 create mode 100644 wcfsetup/install/files/style/recaptcha.less

diff --git a/com.woltlab.wcf/option.xml b/com.woltlab.wcf/option.xml
index e0023f86e9..e006d58102 100644
--- a/com.woltlab.wcf/option.xml
+++ b/com.woltlab.wcf/option.xml
@@ -103,6 +103,10 @@
 				<category name="security.antispam">
 					<parent>security</parent>
 				</category>
+					<category name="security.antispam.recaptcha">
+						<parent>security.antispam</parent>
+					</category>
+				
 				<category name="security.censorship">
 					<parent>security</parent>
 				</category>
@@ -159,6 +163,12 @@
 				<defaultvalue>1</defaultvalue>
 			</option>
 			
+			<option name="module_system_recaptcha">
+				<categoryname>module.system</categoryname>
+				<optiontype>boolean</optiontype>
+				<defaultvalue>1</defaultvalue>
+			</option>
+			
 			<!-- general.page -->
 			<option name="page_title">
 				<categoryname>general.page</categoryname>
@@ -313,6 +323,24 @@ imagick:wcf.acp.option.image_adapter_type.imagick]]>
 			</option>
 			<!-- /security.blacklist -->
 			
+			<option name="recaptcha_publickey">
+				<categoryname>security.antispam.recaptcha</categoryname>
+				<optiontype>text</optiontype>
+				<validationpattern>^[^/]*$</validationpattern>
+				<!-- wcf-recaptcha.woltlab.com global key -->
+				<defaultvalue>6LfOlMYSAAAAADvo3s4puBAYDqI-6YK2ybe7BJE5</defaultvalue>
+				<showorder>1</showorder>
+			</option>
+			
+			<option name="recaptcha_privatekey">
+				<categoryname>security.antispam.recaptcha</categoryname>
+				<optiontype>text</optiontype>
+				<validationpattern>^[^/]*$</validationpattern>
+				<!-- wcf-recaptcha.woltlab.com global key -->
+				<defaultvalue>6LfOlMYSAAAAAKR3m_EFxmDv1xS8PCfeaSZ2LdG9</defaultvalue>
+				<showorder>2</showorder>
+			</option>
+			
 			<!-- general.system.date -->
 			<option name="timezone">
 				<categoryname>general.system.date</categoryname>
diff --git a/com.woltlab.wcf/template/recaptcha.tpl b/com.woltlab.wcf/template/recaptcha.tpl
new file mode 100644
index 0000000000..c8aa647afc
--- /dev/null
+++ b/com.woltlab.wcf/template/recaptcha.tpl
@@ -0,0 +1,55 @@
+<fieldset>
+	<legend><label for="recaptcha_response_field">{lang}wcf.recaptcha.title{/lang}</label></legend>
+	<small>{lang}wcf.recaptcha.description{/lang}</small>
+	
+	<dl class="wide reCaptcha{if $errorField == 'recaptchaString'} formError{/if}">
+		<script type="text/javascript">
+			//<![CDATA[
+			var RecaptchaOptions = {
+				lang: '{@$recaptchaLanguageCode}',
+				theme : 'custom'
+			}
+			//]]>
+		</script>
+		<dt class="jsOnly">
+			<label for="recaptcha_response_field">reCAPTCHA</label>
+		</dt>
+		<dd class="jsOnly">
+			<div id="recaptcha_image" class="framed"></div>
+			<input type="text" id="recaptcha_response_field" name="recaptcha_response_field" class="medium marginTop" />
+			{if $errorField == 'recaptchaString'}
+				<small class="innerError">
+					{if $errorType == 'empty'}{lang}wcf.global.form.error.empty{/lang}{/if}
+					{if $errorType == 'false'}{lang}wcf.recaptcha.error.recaptchaString.false{/lang}{/if}
+				</small>
+			{/if}
+		</dd>
+		
+		{event name='fields'}
+		
+		<dd class="jsOnly">
+			<ul class="buttonList">
+				<li><a href="javascript:Recaptcha.reload()" class="button small"><span class="icon icon16 icon-repeat"></span> <span>{lang}wcf.recaptcha.reload{/lang}</span></a></li>
+				<li class="recaptcha_only_if_image"><a href="javascript:Recaptcha.switch_type('audio')" class="button small"><span class="icon icon16 icon-volume-up"></span> <span>{lang}wcf.recaptcha.audio{/lang}</span></a></li>
+				<li class="recaptcha_only_if_audio"><a href="javascript:Recaptcha.switch_type('image')" class="button small"><span class="icon icon16 icon-eye-open"></span> <span>{lang}wcf.recaptcha.image{/lang}</span></a></li>
+				<li><a href="javascript:Recaptcha.showhelp()" class="button small"><span class="icon icon16 icon-question-sign"></span> <span>{lang}wcf.recaptcha.help{/lang}</span></a></li>
+				{event name='buttons'}
+			</ul>
+		</dd>
+		
+		<script type="text/javascript" src="http{if $recaptchaUseSSL}s{/if}://www.google.com/recaptcha/api/challenge?k={$recaptchaPublicKey}"></script>
+		<noscript>
+			<dd>
+				<iframe src="http{if $recaptchaUseSSL}s{/if}://www.google.com/recaptcha/api/noscript?k={$recaptchaPublicKey}" height="300" width="500" seamless="seamless"></iframe><br />
+				<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
+				<input type="hidden" name="recaptcha_response_field" value="manual_challenge" />
+			</dd>
+			{if $errorField == 'recaptchaString'}
+				<small class="innerError">
+					{if $errorType == 'empty'}{lang}wcf.global.form.error.empty{/lang}{/if}
+					{if $errorType == 'false'}{lang}wcf.recaptcha.error.recaptchaString.false{/lang}{/if}
+				</small>
+			{/if}
+		</noscript>
+	</dl>
+</fieldset>
diff --git a/wcfsetup/install/files/lib/form/RecaptchaForm.class.php b/wcfsetup/install/files/lib/form/RecaptchaForm.class.php
new file mode 100644
index 0000000000..3728bdded6
--- /dev/null
+++ b/wcfsetup/install/files/lib/form/RecaptchaForm.class.php
@@ -0,0 +1,96 @@
+<?php
+namespace wcf\form;
+use wcf\system\recaptcha\RecaptchaHandler;
+use wcf\system\WCF;
+use wcf\util\StringUtil;
+
+/**
+ * RecaptchaForm is an abstract form implementation for the use of reCAPTCHA.
+ * 
+ * @author	Marcel Werk
+ * @copyright	2001-2013 WoltLab GmbH
+ * @license	GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package	com.woltlab.wcf.recaptcha
+ * @subpackage	form
+ * @category	Community Framework
+ */
+abstract class RecaptchaForm extends AbstractForm {
+	/**
+	 * challenge
+	 * @var	string
+	 */
+	public $challenge = '';
+	
+	/**
+	 * response
+	 * @var	string
+	 */
+	public $response = '';
+	
+	/**
+	 * enable recaptcha
+	 * @var	boolean
+	 */
+	public $useCaptcha = true;
+	
+	/**
+	 * @see	wcf\page\IPage::readParameters()
+	 */
+	public function readParameters() {
+		parent::readParameters();
+		
+		if (WCF::getUser()->userID || WCF::getSession()->getVar('recaptchaDone')) {
+			$this->useCaptcha = false;
+		}
+	}
+	
+	/**
+	 * @see	wcf\form\IForm::readFormParameters()
+	 */
+	public function readFormParameters() {
+		parent::readFormParameters();
+		
+		if (isset($_POST['recaptcha_challenge_field'])) $this->challenge = StringUtil::trim($_POST['recaptcha_challenge_field']);
+		if (isset($_POST['recaptcha_response_field'])) $this->response = StringUtil::trim($_POST['recaptcha_response_field']);
+	}
+	
+	/**
+	 * @see	wcf\form\IForm::validate()
+	 */
+	public function validate() {
+		parent::validate();
+		
+		$this->validateCaptcha();
+	}
+	
+	/**
+	 * Validates the captcha.
+	 */
+	protected function validateCaptcha() {
+		if ($this->useCaptcha) {
+			RecaptchaHandler::getInstance()->validate($this->challenge, $this->response);
+			$this->useCaptcha = false;
+		}
+	}
+	
+	/**
+	 * @see	wcf\form\IForm::save()
+	 */
+	public function save() {
+		parent::save();
+		
+		WCF::getSession()->unregister('recaptchaDone');
+	}
+	
+	/**
+	 * @see	wcf\page\IPage::assignVariables()
+	 */
+	public function assignVariables() {
+		parent::assignVariables();
+		
+		RecaptchaHandler::getInstance()->assignVariables();
+		WCF::getTPL()->assign(array(
+			'useCaptcha' => $this->useCaptcha
+		));
+	}
+}
diff --git a/wcfsetup/install/files/lib/system/recaptcha/RecaptchaHandler.class.php b/wcfsetup/install/files/lib/system/recaptcha/RecaptchaHandler.class.php
new file mode 100644
index 0000000000..5c385204cc
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/recaptcha/RecaptchaHandler.class.php
@@ -0,0 +1,180 @@
+<?php
+namespace wcf\system\recaptcha;
+use wcf\system\exception\SystemException;
+use wcf\system\exception\UserInputException;
+use wcf\system\request\RouteHandler;
+use wcf\system\SingletonFactory;
+use wcf\system\WCF;
+use wcf\util\HTTPRequest;
+use wcf\util\StringUtil;
+use wcf\util\UserUtil;
+
+/**
+ * Handles reCAPTCHA support.
+ * 
+ * Based upon reCAPTCHA-plugin originally created in 2010 by Markus Bartz <roul@codingcorner.info>
+ * and released under the conditions of the GNU Lesser General Public License.
+ * 
+ * @author	Alexander Ebert
+ * @copyright	2001-2013 WoltLab GmbH
+ * @license	GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package	com.woltlab.wcf.recaptcha
+ * @subpackage	system.recaptcha
+ * @category	Community Framework
+ */
+class RecaptchaHandler extends SingletonFactory {
+	/**
+	 * list of supported languages
+	 * @var	array<string>
+	 * @see	http://code.google.com/intl/de-DE/apis/recaptcha/docs/customization.html#i18n
+	 */
+	protected $supportedLanguages = array(
+		'de', 'en', 'es', 'fr', 'nl', 'pt', 'ru', 'tr'
+	);
+	
+	/**
+	 * language code
+	 * @var	string
+	 */
+	protected $languageCode = '';
+	
+	/**
+	 * public key
+	 * @var	string
+	 */
+	protected $publicKey = '';
+	
+	/**
+	 * private key
+	 * @var	string
+	 */
+	protected $privateKey = '';
+	
+	// reply codes (see <http://code.google.com/intl/de-DE/apis/recaptcha/docs/verify.html>)
+	const VALID_ANSWER = 'valid';
+	const ERROR_UNKNOWN = 'unknown';
+	const ERROR_INVALID_PUBLICKEY = 'invalid-site-public-key';
+	const ERROR_INVALID_PRIVATEKEY = 'invalid-site-private-key';
+	const ERROR_INVALID_COOKIE = 'invalid-request-cookie';
+	const ERROR_INCORRECT_SOLUTION = 'incorrect-captcha-sol';
+	const ERROR_INCORRECT_PARAMS = 'verify-params-incorrect';
+	const ERROR_INVALID_REFFERER = 'invalid-referrer';
+	const ERROR_NOT_REACHABLE = 'recaptcha-not-reachable';
+	
+	/**
+	 * @see	wcf\system\SingletonFactory::init()
+	 */
+	protected function init() {
+		// set appropriate language code, fallback to EN if language code is not known to reCAPTCHA-API
+		$this->languageCode = WCF::getLanguage()->getFixedLanguageCode();
+		if (!in_array($this->languageCode, $this->supportedLanguages)) {
+			$this->languageCode = 'en';
+		}
+		
+		// fetch appropriate keys
+		$this->publicKey = $this->getKey(RECAPTCHA_PUBLICKEY, 'public');
+		$this->privateKey = $this->getKey(RECAPTCHA_PRIVATEKEY, 'private');
+	}
+	
+	/**
+	 * Returns appropriate public or private key, supports multiple hosts.
+	 * 
+	 * @param	string		$pubKey
+	 * @param	string		$type
+	 * @return	string
+	 */
+	protected function getKey($pubKey, $type) {
+		// check if multiple keys are given
+		$keys = explode("\n", $pubKey);
+		if (count($keys) > 1) {
+			foreach ($keys as $key) {
+				$keyParts = explode(':', $key);
+				
+				if (StringUtil::trim($keyParts[0]) == $_SERVER['HTTP_HOST']) {
+					return StringUtil::trim($keyParts[1]);
+				}
+			}
+		}
+		else {
+			return $pubKey;
+		}
+		
+		throw new SystemException('No valid '.$type.' key for reCAPTCHA found.');
+	}
+	
+	/**
+	 * Validates response against given challenge.
+	 * 
+	 * @param	string		$challenge
+	 * @param	string		$response
+	 */
+	public function validate($challenge, $response) {
+		// fail if challenge or response are empty to avoid sending api requests
+		if (empty($challenge) || empty($response)) {
+			throw new UserInputException('recaptchaString', 'false');
+		}
+		
+		$response = $this->verify($challenge, $response);
+		switch ($response) {
+			case self::VALID_ANSWER:
+				break;
+			
+			case self::ERROR_INCORRECT_SOLUTION:
+				throw new UserInputException('recaptchaString', 'false');
+				break;
+			
+			case self::ERROR_NOT_REACHABLE:
+				// if reCaptcha server is unreachable mark captcha as done
+				// this should be better than block users until server is back.
+				// - RouL
+				break;
+			
+			default:
+				throw new SystemException('reCAPTCHA returned the following error: '.$response);
+		}
+		
+		WCF::getSession()->register('recaptchaDone', true);
+	}
+	
+	/**
+	 * Queries server to verify successful response.
+	 * 
+	 * @param	string		$challenge
+	 * @param	string		$response
+	 */
+	protected function verify($challenge, $response) {
+		$request = new HTTPRequest('http://www.google.com/recaptcha/api/verify', array(), array(
+			'privatekey' => $this->privateKey,
+			'remoteip' => UserUtil::getIpAddress(),
+			'challenge' => $challenge,
+			'response' => $response
+		));
+		
+		try {
+			$request->execute();
+			$reply = $request->getReply();
+			$reCaptchaResponse = explode("\n", $reply['body']);
+			
+			if (StringUtil::trim($reCaptchaResponse[0]) === "true") {
+				return self::VALID_ANSWER;
+			}
+			else {
+				return StringUtil::trim($reCaptchaResponse[1]);
+			}
+		}
+		catch (SystemException $e) {
+			return self::ERROR_NOT_REACHABLE;
+		}
+	}
+	
+	/**
+	 * Assigns template variables for reCAPTCHA.
+	 */
+	public function assignVariables() {
+		WCF::getTPL()->assign(array(
+			'recaptchaLanguageCode' => $this->languageCode,
+			'recaptchaPublicKey' => $this->publicKey,
+			'recaptchaUseSSL' => RouteHandler::secureConnection()
+		));
+	}
+}
diff --git a/wcfsetup/install/files/style/recaptcha.less b/wcfsetup/install/files/style/recaptcha.less
new file mode 100644
index 0000000000..4a3ec50716
--- /dev/null
+++ b/wcfsetup/install/files/style/recaptcha.less
@@ -0,0 +1,5 @@
+.reCaptcha {
+	input.marginTop {
+		margin-top: 14px;
+	}
+}
\ No newline at end of file
diff --git a/wcfsetup/install/lang/de.xml b/wcfsetup/install/lang/de.xml
index 03e73b0672..66a26a4ba4 100644
--- a/wcfsetup/install/lang/de.xml
+++ b/wcfsetup/install/lang/de.xml
@@ -325,7 +325,6 @@
 		<item name="wcf.acp.option.cache_source_type.disk"><![CDATA[Dateisystem (Standard)]]></item>
 		<item name="wcf.acp.option.cache_source_type.memcached"><![CDATA[Memcached]]></item>
 		<item name="wcf.acp.option.cache_source_type.no"><![CDATA[Caching deaktivieren (Nicht empfohlen)]]></item>
-		
 		<item name="wcf.acp.option.category.general"><![CDATA[Allgemein]]></item>
 		<item name="wcf.acp.option.category.general.cache"><![CDATA[Cache]]></item>
 		<item name="wcf.acp.option.category.general.cache.general"><![CDATA[Allgemein]]></item>
@@ -360,42 +359,34 @@
 		<item name="wcf.acp.option.category.security.antispam"><![CDATA[Anti-Spam]]></item>
 		<item name="wcf.acp.option.category.security.censorship"><![CDATA[Zensur]]></item>
 		<item name="wcf.acp.option.category.general.system.jquery"><![CDATA[jQuery]]></item>
-		
 		<item name="wcf.acp.option.cookie_domain"><![CDATA[Cookiedomain]]></item>
 		<item name="wcf.acp.option.cookie_domain.description"><![CDATA[Standardmäßig sollten Sie dieses Feld frei lassen, da ein Ausfüllen nur in wenigen Fällen notwendig ist.]]></item>
 		<item name="wcf.acp.option.cookie_path"><![CDATA[Cookiepfad]]></item>
 		<item name="wcf.acp.option.cookie_path.description"><![CDATA[Der Cookiepfad wird absolut zum Document Root angegeben - also z.B. "/forum" für http://www.woltlab.de/forum.]]></item>
 		<item name="wcf.acp.option.cookie_prefix"><![CDATA[Präfix für Cookienamen]]></item>
-		
 		<item name="wcf.acp.option.error.tooHigh"><![CDATA[Der angegebene Wert ist zu hoch.{if $option->maxvalue !== null} Der maximale Wert ist {#$option->maxvalue}.{/if}]]></item>
 		<item name="wcf.acp.option.error.tooLow"><![CDATA[Der angegebene Wert ist zu gering.{if $option->minvalue !== null} Der minimale Wert ist {#$option->minvalue}.{/if}]]></item>
-		
 		<item name="wcf.acp.option.export"><![CDATA[Optionen sichern]]></item>
 		<item name="wcf.acp.option.export.download"><![CDATA[Sicherung der Optionen herunterladen]]></item>
 		<item name="wcf.acp.option.export.download.description"><![CDATA[Laden Sie eine Sicherung der Optionen auf Ihren lokalen Rechner herunter.]]></item>
-		
 		<item name="wcf.acp.option.http_enable_gzip"><![CDATA[Gzip-Komprimierung aktivieren]]></item>
 		<item name="wcf.acp.option.http_enable_gzip.description"><![CDATA[Aktiviert die Komprimierung der Inhalte bei der Übertragung vom Server an den Client. Dies reduziert den Traffic und kann den Ladevorgang erheblich beschleunigen.]]></item>
 		<item name="wcf.acp.option.http_enable_no_cache_headers"><![CDATA[Seitencaching im Client-Browser verhindern]]></item>
 		<item name="wcf.acp.option.http_enable_no_cache_headers.description"><![CDATA[Verhindert zuverlässig das Cachen von einzelnen Seiten und sorgt somit dafür, dass beim Seitenaufruf immer die neueste Version der Seite geladen wird. Führt umgekehrt aber zu höherem Traffic und mehr Serverlast.]]></item>
-		
 		<item name="wcf.acp.option.http_gzip_level"><![CDATA[Gzip-Komprimierungslevel]]></item>
 		<item name="wcf.acp.option.http_gzip_level.description"><![CDATA[Werte von 1-9 sind zulässig. Als Optimum zwischen Komprimierung und Serverlast empfiehlt sich Level 1.]]></item>
 		<item name="wcf.acp.option.image_adapter_type"><![CDATA[Grafik-Bibliothek]]></item>
 		<item name="wcf.acp.option.image_adapter_type.gd"><![CDATA[GD Library (Standard)]]></item>
 		<item name="wcf.acp.option.image_adapter_type.imagick"><![CDATA[ImageMagick]]></item>
 		<item name="wcf.acp.option.image_adapter_type.description"><![CDATA[Bibliothek für die Generierung von Grafiken, wird z.B. für die Skalierung von hochgeladenen Bildern verwendet. „ImageMagick“ ist in der Regel deutlich schneller, steht aber nicht auf jedem Server zur Verfügung.]]></item>
-		
 		<item name="wcf.acp.option.import"><![CDATA[Optionen importieren]]></item>
 		<item name="wcf.acp.option.import.error.importFailed"><![CDATA[Die Optionen konnten nicht erfolgreich importiert werden.]]></item>
 		<item name="wcf.acp.option.import.success"><![CDATA[Die Optionen wurden erfolgreich importiert.]]></item>
 		<item name="wcf.acp.option.import.upload"><![CDATA[Sicherung der Optionen vom lokalen Computer hochladen]]></item>
 		<item name="wcf.acp.option.import.upload.description"><![CDATA[Wählen Sie eine Sicherung der Optionen von Ihrem lokalen Rechner aus.]]></item>
 		<item name="wcf.acp.option.importAndExport"><![CDATA[Optionen sichern &amp; wiederherstellen]]></item>
-		
 		<item name="wcf.acp.option.log_ip_address"><![CDATA[Speicherung von IP-Adressen]]></item>
 		<item name="wcf.acp.option.log_ip_address.description"><![CDATA[Aktiviert die Speicherung von IP-Adressen der Benutzer in z.B. Sitzungen, Benutzerprofilen, Forenbeiträgen.]]></item>
-		
 		<item name="wcf.acp.option.mail_admin_address"><![CDATA[Administrator-Adresse]]></item>
 		<item name="wcf.acp.option.mail_admin_address.description"><![CDATA[E-Mail-Adresse des Administrators]]></item>
 		<item name="wcf.acp.option.mail_debug_logfile_path"><![CDATA[Debug Logfile-Pfad]]></item>
@@ -457,6 +448,12 @@
 		<item name="wcf.acp.option.package_server_auth_code"><![CDATA[Authentifizierung-Code]]></item>
 		<item name="wcf.acp.option.package_server_auth_code.description"><![CDATA[Ihren Authentifizierung-Code finden Sie in Ihrem Kundenkonto auf woltlab.com.]]></item>
 		<item name="wcf.acp.option.enable_woltlab_news"><![CDATA[WoltLab-Nachrichten auf der Startseite der Administrationsoberfläche anzeigen]]></item>
+		<item name="wcf.acp.option.module_system_recaptcha"><![CDATA[Sicherheitsabfragen („reCAPTCHA“)]]></item>
+		<item name="wcf.acp.option.module_system_recaptcha.description"><![CDATA[Aktiviert Sicherheitsabfragen um das automatisierte Absenden von Formular durch so genannte Bots zu verhindern.]]></item>
+		<item name="wcf.acp.option.category.security.antispam.recaptcha"><![CDATA[reCAPTCHA]]></item>
+		<item name="wcf.acp.option.recaptcha_publickey"><![CDATA[Public-API-Key]]></item>
+		<item name="wcf.acp.option.recaptcha_publickey.description"><![CDATA[Einen eigenen API-Key für die Nutzung der reCAPTCHA-Funktion können Sie auf der Website von <a href="https://www.google.com/recaptcha/admin/create" class="externalURL">reCAPTCHA</a> beantragen.]]></item>
+		<item name="wcf.acp.option.recaptcha_privatekey"><![CDATA[Private-API-Key]]></item>
 	</category>
 	
 	<category name="wcf.acp.package">
@@ -1128,6 +1125,16 @@ Wenn Sie unter <em>System -&gt; Optionen -&gt; Allgemein -&gt; E-Mails</em> alle
 		<item name="wcf.page.pagePosition"><![CDATA[Seite {#$pageNo} von {#$pages}]]></item>
 	</category>
 	
+	<category name="wcf.recaptcha">
+		<item name="wcf.recaptcha.title"><![CDATA[Sicherheitsabfrage („reCAPTCHA“)]]></item>
+		<item name="wcf.recaptcha.description"><![CDATA[Bitte geben Sie die untenstehenden Zeichen in das leere Feld ein. Groß- und Kleinschreibung müssen nicht beachtet werden. Sollten Sie das Bild trotz Neuladen nicht identifizieren können, wenden Sie sich an den Administrator.]]></item>
+		<item name="wcf.recaptcha.reload"><![CDATA[Neuladen]]></item>
+		<item name="wcf.recaptcha.audio"><![CDATA[Audio-Version]]></item>
+		<item name="wcf.recaptcha.image"><![CDATA[Bild-Version]]></item>
+		<item name="wcf.recaptcha.help"><![CDATA[Hilfe]]></item>
+		<item name="wcf.recaptcha.error.recaptchaString.false"><![CDATA[Sie haben leider nicht die korrekten Zeichen eingegeben. Bitte versuchen Sie es erneut!]]></item>
+	</category>
+	
 	<category name="wcf.style">
 		<item name="wcf.style.changeStyle"><![CDATA[Stil ändern]]></item>
 		<item name="wcf.style.colorPicker"><![CDATA[Farbwähler]]></item>
diff --git a/wcfsetup/install/lang/en.xml b/wcfsetup/install/lang/en.xml
index cadfbe517d..bf8f4d0c86 100644
--- a/wcfsetup/install/lang/en.xml
+++ b/wcfsetup/install/lang/en.xml
@@ -325,7 +325,6 @@
 		<item name="wcf.acp.option.cache_source_type.disk"><![CDATA[Filesystem (default)]]></item>
 		<item name="wcf.acp.option.cache_source_type.memcached"><![CDATA[Memcached]]></item>
 		<item name="wcf.acp.option.cache_source_type.no"><![CDATA[Disable caching (not recommended)]]></item>
-		
 		<item name="wcf.acp.option.category.general"><![CDATA[General]]></item>
 		<item name="wcf.acp.option.category.general.cache"><![CDATA[Cache]]></item>
 		<item name="wcf.acp.option.category.general.cache.general"><![CDATA[General]]></item>
@@ -360,42 +359,34 @@
 		<item name="wcf.acp.option.category.security.antispam"><![CDATA[Anti-Spam]]></item>
 		<item name="wcf.acp.option.category.security.censorship"><![CDATA[Censorship]]></item>
 		<item name="wcf.acp.option.category.general.system.jquery"><![CDATA[jQuery]]></item>
-		
 		<item name="wcf.acp.option.cookie_domain"><![CDATA[Cookie Domain]]></item>
 		<item name="wcf.acp.option.cookie_domain.description"><![CDATA[Should be left blank except for special circumstances.]]></item>
 		<item name="wcf.acp.option.cookie_path"><![CDATA[Cookie Path]]></item>
 		<item name="wcf.acp.option.cookie_path.description"><![CDATA[Value should be absolute to Document Root, e.g. “/forum” for “http://www.woltlab.com/forum”.]]></item>
 		<item name="wcf.acp.option.cookie_prefix"><![CDATA[Cookie Prefix]]></item>
-		
 		<item name="wcf.acp.option.error.tooHigh"><![CDATA[Exceeds the maximum value{if $option->maxvalue !== null} of {#$option->maxvalue}{/if}.]]></item>
 		<item name="wcf.acp.option.error.tooLow"><![CDATA[Below the minimum value{if $option->minvalue !== null} of {#$option->minvalue}{/if}.]]></item>
-		
 		<item name="wcf.acp.option.export"><![CDATA[Download Options]]></item>
 		<item name="wcf.acp.option.export.download"><![CDATA[Download Options]]></item>
 		<item name="wcf.acp.option.export.download.description"><![CDATA[Downloads a backup of the configuration settings to your local machine. This is not a replacement for a backup!]]></item>
-		
 		<item name="wcf.acp.option.http_enable_gzip"><![CDATA[Enable gzip-compression]]></item>
 		<item name="wcf.acp.option.http_enable_gzip.description"><![CDATA[Compresses content transfered to users, reduces traffic and page load time. Does not affect files, e.g. images.]]></item>
 		<item name="wcf.acp.option.http_enable_no_cache_headers"><![CDATA[Prevent Browser-caching]]></item>
 		<item name="wcf.acp.option.http_enable_no_cache_headers.description"><![CDATA[Prevents Browser’s caching ensuring your users are always viewing the latest content. Increases both traffic and server load.]]></item>
-		
 		<item name="wcf.acp.option.http_gzip_level"><![CDATA[gzip-compression level]]></item>
 		<item name="wcf.acp.option.http_gzip_level.description"><![CDATA[Values between 1 and 9 are valid, it is recommended to use “1” for good compression without causing high server loads.]]></item>
 		<item name="wcf.acp.option.image_adapter_type"><![CDATA[Graphics Library]]></item>
 		<item name="wcf.acp.option.image_adapter_type.gd"><![CDATA[GD Library (default)]]></item>
 		<item name="wcf.acp.option.image_adapter_type.imagick"><![CDATA[ImageMagick]]></item>
 		<item name="wcf.acp.option.image_adapter_type.description"><![CDATA[Library used for image processing, e.g. scaling uploaded images. “ImageMagick” is a lot faster, but is not available on every machine.]]></item>
-		
 		<item name="wcf.acp.option.import"><![CDATA[Restore Options]]></item>
 		<item name="wcf.acp.option.import.error.importFailed"><![CDATA[Unable to restore options.]]></item>
 		<item name="wcf.acp.option.import.success"><![CDATA[Options have been restored.]]></item>
 		<item name="wcf.acp.option.import.upload"><![CDATA[Upload Options]]></item>
 		<item name="wcf.acp.option.import.upload.description"><![CDATA[Upload previously downloaded options file.]]></item>
 		<item name="wcf.acp.option.importAndExport"><![CDATA[Save &amp; Restore Options]]></item>
-		
 		<item name="wcf.acp.option.log_ip_address"><![CDATA[Store IP addresses]]></item>
 		<item name="wcf.acp.option.log_ip_address.description"><![CDATA[Stores IP addresses for user-generated content, e.g. sessions, profiles or forum posts.]]></item>
-		
 		<item name="wcf.acp.option.mail_admin_address"><![CDATA[Administrator]]></item>
 		<item name="wcf.acp.option.mail_admin_address.description"><![CDATA[Administrator’s email address]]></item>
 		<item name="wcf.acp.option.mail_debug_logfile_path"><![CDATA[Debug Log Filename]]></item>
@@ -457,6 +448,12 @@
 		<item name="wcf.acp.option.package_server_auth_code"><![CDATA[Authentication Code]]></item>
 		<item name="wcf.acp.option.package_server_auth_code.description"><![CDATA[Your authentication code is available in the customers area on woltlab.com.]]></item>
 		<item name="wcf.acp.option.enable_woltlab_news"><![CDATA[Show WoltLab news on the administration control panel’s start page.]]></item>
+		<item name="wcf.acp.option.module_system_recaptcha"><![CDATA[Verification (“reCAPTCHA”)]]></item>
+		<item name="wcf.acp.option.module_system_recaptcha.description"><![CDATA[Enables security measures to prevent automatic form submission for bots.]]></item>
+		<item name="wcf.acp.option.category.security.antispam.recaptcha"><![CDATA[reCAPTCHA]]></item>
+		<item name="wcf.acp.option.recaptcha_publickey"><![CDATA[Public API Key]]></item>
+		<item name="wcf.acp.option.recaptcha_publickey.description"><![CDATA[You can request an own API-Key for using reCAPTCHA on the <a href="https://www.google.com/recaptcha/admin/create" class="externalURL">reCAPTCHA website</a>.]]></item>
+		<item name="wcf.acp.option.recaptcha_privatekey"><![CDATA[Private API Key]]></item>
 	</category>
 	
 	<category name="wcf.acp.package">
@@ -1128,6 +1125,16 @@ You can define the default sender in <em>System -&gt; Options -&gt; General -&gt
 		<item name="wcf.page.pagePosition"><![CDATA[Page {#$pageNo} of {#$pages}]]></item>
 	</category>
 	
+	<category name="wcf.recaptcha">
+		<item name="wcf.recaptcha.title"><![CDATA[Verification (“reCAPTCHA”)]]></item>
+		<item name="wcf.recaptcha.description"><![CDATA[Please enter the letters that are shown in the picture below (letters are not case-sensitive). If you cannot identify the captcha even after reloading it, please contact the administrator.]]></item>
+		<item name="wcf.recaptcha.reload"><![CDATA[Reload]]></item>
+		<item name="wcf.recaptcha.audio"><![CDATA[Audio Version]]></item>
+		<item name="wcf.recaptcha.image"><![CDATA[Image Version]]></item>
+		<item name="wcf.recaptcha.help"><![CDATA[Help]]></item>
+		<item name="wcf.recaptcha.error.recaptchaString.false"><![CDATA[You have entered the security code incorrectly. Please try again.]]></item>
+	</category>
+	
 	<category name="wcf.style">
 		<item name="wcf.style.changeStyle"><![CDATA[Change Style]]></item>
 		<item name="wcf.style.colorPicker"><![CDATA[Color Picker]]></item>
-- 
2.20.1