diff --git a/lam/help/help.inc b/lam/help/help.inc
index 516f2a75..d176dba1 100644
--- a/lam/help/help.inc
+++ b/lam/help/help.inc
@@ -311,6 +311,10 @@ $helpArray = array (
 					"Text" => _('Protect the self service login with a captcha.')),
 				"523" => array ("Headline" => _('Base color'),
 					"Text" => _('Background color for self service pages.')),
+				"524" => array ("Headline" => _('Client id'),
+					"Text" => _('Please enter your client id for the verification API.')),
+				"525" => array ("Headline" => _('Secret key'),
+					"Text" => _('Please enter your secret key for the verification API.')),
 				"550" => array ("Headline" => _("From address"),
 					"Text" => _("This email address will be set as sender address of all password mails. If empty the system default (php.ini) will be used.")),
 				"551" => array ("Headline" => _("Subject"),
diff --git a/lam/lib/2factor.inc b/lam/lib/2factor.inc
index f4907667..7bccb039 100644
--- a/lam/lib/2factor.inc
+++ b/lam/lib/2factor.inc
@@ -53,6 +53,8 @@ interface TwoFactorProvider {
 	 */
 	public function verify2ndFactor($user, $password, $serial, $twoFactorInput);
 
+
+
 }
 
 /**
@@ -223,6 +225,71 @@ class PrivacyIDEAProvider implements TwoFactorProvider {
 
 }
 
+/**
+ * Authentication via YubiKeys.
+ *
+ * @author Roland Gruber
+ */
+class YubicoProvider implements TwoFactorProvider {
+
+	private $config;
+
+	/**
+	 * Constructor.
+	 *
+	 * @param TwoFactorConfiguration $config configuration
+	 */
+	public function __construct(&$config) {
+		$this->config = $config;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 * @see \LAM\LIB\TWO_FACTOR\TwoFactorProvider::getSerials()
+	 */
+	public function getSerials($user, $password) {
+		$keyAttributeName = strtolower('yubiKeyId');
+		$loginDn = $_SESSION['ldap']->getUserName();
+		$handle = getLDAPServerHandle();
+		$ldapData = ldapGetDN($loginDn, array($keyAttributeName), $handle);
+		if (empty($ldapData[$keyAttributeName])) {
+			return array();
+		}
+		return array(implode(', ', $ldapData[$keyAttributeName]));
+	}
+
+	/**
+	 * {@inheritDoc}
+	 * @see \LAM\LIB\TWO_FACTOR\TwoFactorProvider::verify2ndFactor()
+	 */
+	public function verify2ndFactor($user, $password, $serial, $twoFactorInput) {
+		include_once(__DIR__ . "/3rdParty/yubico/Yubico.php");
+		$serialData = $this->getSerials($user, $password);
+		if (empty($serialData)) {
+			return false;
+		}
+		$serials = explode(', ', $serialData[0]);
+		$serialMatched = false;
+		foreach ($serials as $serial) {
+			if (strpos($twoFactorInput, $serial) === 0) {
+				$serialMatched = true;
+				break;
+			}
+		}
+		if (!$serialMatched) {
+			throw new \Exception(_('YubiKey id does not match allowed list of key ids.'));
+		}
+		$url = $this->config->twoFactorAuthenticationURL;
+		$httpsverify = !$this->config->twoFactorAuthenticationInsecure;
+		$clientId = $this->config->twoFactorAuthenticationClientId;
+		$secretKey = $this->config->twoFactorAuthenticationSecretKey;
+		$auth = new \Auth_Yubico($clientId, $secretKey, $url, $httpsverify);
+		$auth->verify($twoFactorInput);
+		return true;
+	}
+
+}
+
 /**
  * Returns the correct 2 factor provider.
  */
@@ -232,6 +299,8 @@ class TwoFactorProviderService {
 	const TWO_FACTOR_NONE = 'none';
 	/** 2factor authentication via privacyIDEA */
 	const TWO_FACTOR_PRIVACYIDEA = 'privacyidea';
+	/** 2factor authentication via YubiKey */
+	const TWO_FACTOR_YUBICO = 'yubico';
 
 	private $config;
 
@@ -260,6 +329,9 @@ class TwoFactorProviderService {
 		if ($this->config->twoFactorAuthentication == TwoFactorProviderService::TWO_FACTOR_PRIVACYIDEA) {
 			return new PrivacyIDEAProvider($this->config);
 		}
+		elseif ($this->config->twoFactorAuthentication == TwoFactorProviderService::TWO_FACTOR_YUBICO) {
+			return new YubicoProvider($this->config);
+		}
 		throw new \Exception('Invalid provider: ' . $this->config->twoFactorAuthentication);
 	}
 
@@ -270,11 +342,11 @@ class TwoFactorProviderService {
 	 * @return TwoFactorConfiguration configuration
 	 */
 	private function getConfigSelfService(&$profile) {
-		$config = new TwoFactorConfiguration();
-		$config->twoFactorAuthentication = $profile->twoFactorAuthentication;
-		$config->twoFactorAuthenticationInsecure = $profile->twoFactorAuthenticationInsecure;
-		$config->twoFactorAuthenticationURL = $profile->twoFactorAuthenticationURL;
-		return $config;
+		$tfConfig = new TwoFactorConfiguration();
+		$tfConfig->twoFactorAuthentication = $profile->twoFactorAuthentication;
+		$tfConfig->twoFactorAuthenticationInsecure = $profile->twoFactorAuthenticationInsecure;
+		$tfConfig->twoFactorAuthenticationURL = $profile->twoFactorAuthenticationURL;
+		return $tfConfig;
 	}
 
 	/**
@@ -284,11 +356,13 @@ class TwoFactorProviderService {
 	 * @return TwoFactorConfiguration configuration
 	 */
 	private function getConfigAdmin($conf) {
-		$config = new TwoFactorConfiguration();
-		$config->twoFactorAuthentication = $conf->getTwoFactorAuthentication();
-		$config->twoFactorAuthenticationInsecure = $conf->getTwoFactorAuthenticationInsecure();
-		$config->twoFactorAuthenticationURL = $conf->getTwoFactorAuthenticationURL();
-		return $config;
+		$tfConfig = new TwoFactorConfiguration();
+		$tfConfig->twoFactorAuthentication = $conf->getTwoFactorAuthentication();
+		$tfConfig->twoFactorAuthenticationInsecure = $conf->getTwoFactorAuthenticationInsecure();
+		$tfConfig->twoFactorAuthenticationURL = $conf->getTwoFactorAuthenticationURL();
+		$tfConfig->twoFactorAuthenticationClientId = $conf->getTwoFactorAuthenticationClientId();
+		$tfConfig->twoFactorAuthenticationSecretKey = $conf->getTwoFactorAuthenticationSecretKey();
+		return $tfConfig;
 	}
 
 }
@@ -299,7 +373,30 @@ class TwoFactorProviderService {
  * @author Roland Gruber
  */
 class TwoFactorConfiguration {
+
+	/**
+	 * @var string provider id
+	 */
 	public $twoFactorAuthentication = null;
+
+	/**
+	 * @var service URL
+	 */
 	public $twoFactorAuthenticationURL = null;
+
+	/**
+	 * @var disable certificate check
+	 */
 	public $twoFactorAuthenticationInsecure = false;
+
+	/**
+	 * @var client ID for API access
+	 */
+	public $twoFactorAuthenticationClientId = null;
+
+	/**
+	 * @var secret key for API access
+	 */
+	public $twoFactorAuthenticationSecretKey = null;
+
 }
diff --git a/lam/lib/3rdParty/yubico/Yubico.php b/lam/lib/3rdParty/yubico/Yubico.php
new file mode 100644
index 00000000..148d6f5f
--- /dev/null
+++ b/lam/lib/3rdParty/yubico/Yubico.php
@@ -0,0 +1,351 @@
+<?php
+/**
+ * Class for verifying Yubico One-Time-Passcodes
+ *
+ * @category Auth
+ * @package Auth_Yubico
+ * @author Simon Josefsson <simon@yubico.com>, Olov Danielson <olov@yubico.com>
+ * @author Roland Gruber
+ * @copyright 2007-2015 Yubico AB
+ * @copyright 2018 Roland Gruber
+ * @license https://opensource.org/licenses/bsd-license.php New BSD License
+ * @version 2.0
+ * @link https://www.yubico.com/
+ *
+ *       Adapted for LAM.
+ */
+
+/**
+ * Class for verifying Yubico One-Time-Passcodes
+ */
+class Auth_Yubico {
+
+	/**
+	 * Yubico client ID
+	 *
+	 * @var string
+	 */
+	private $clientId;
+
+	/**
+	 * Yubico client key
+	 *
+	 * @var string
+	 */
+	private $clientKey;
+
+	/**
+	 * URL part of validation server
+	 *
+	 * @var string
+	 */
+	private $url;
+
+	/**
+	 * Last query to server
+	 *
+	 * @var string
+	 */
+	private $lastquery;
+
+	/**
+	 * Response from server
+	 *
+	 * @var string
+	 */
+	private $response;
+
+	/**
+	 * Flag whether to verify HTTPS server certificates or not.
+	 *
+	 * @var boolean
+	 */
+	private $httpsVerify;
+
+	/**
+	 * Constructor
+	 *
+	 * Sets up the object
+	 *
+	 * @param string $id The client identity
+	 * @param string $key The client MAC key
+	 * @param string $url URL
+	 * @param boolean $httpsverify Flag whether to use verify HTTPS
+	 *        server certificates
+	 */
+	public function __construct($id, $key, $url, $httpsverify) {
+		$this->clientId = $id;
+		$this->clientKey = base64_decode($key);
+		$this->httpsVerify = $httpsverify;
+		$this->url = $url;
+	}
+
+	/**
+	 * Parse input string into password, yubikey prefix,
+	 * ciphertext, and OTP.
+	 *
+	 * @param string Input string to parse
+	 * @param string Optional delimiter re-class, default is '[:]'
+	 * @return array Keyed array with fields
+	 */
+	private function parsePasswordOTP($str, $delim = '[:]') {
+		if (!preg_match("/^((.*)" . $delim . ")?(([cbdefghijklnrtuv]{0,12})([cbdefghijklnrtuv]{32}))$/i", $str, $matches)) {
+			/* Dvorak? */
+			if (!preg_match("/^((.*)" . $delim . ")?(([jxe\\.uidchtnbpygk]{0,12})([jxe\\.uidchtnbpygk]{32}))$/i", $str, $matches)) {
+				return false;
+			}
+			else {
+				$ret['otp'] = strtr($matches[3], "jxe.uidchtnbpygk", "cbdefghijklnrtuv");
+			}
+		}
+		else {
+			$ret['otp'] = $matches[3];
+		}
+		$ret['password'] = $matches[2];
+		$ret['prefix'] = $matches[4];
+		$ret['ciphertext'] = $matches[5];
+		return $ret;
+	}
+
+	/**
+	 * Parse parameters from last response
+	 *
+	 * example: getParameters("timestamp", "sessioncounter", "sessionuse");
+	 *
+	 * @param array @parameters Array with strings representing
+	 *        parameters to parse
+	 * @return array parameter array from last response
+	 */
+	private function getParameters($parameters) {
+		if ($parameters == null) {
+			$parameters = array(
+				'timestamp',
+				'sessioncounter',
+				'sessionuse'
+			);
+		}
+		$param_array = array();
+		foreach ($parameters as $param) {
+			if (!preg_match("/" . $param . "=([0-9]+)/", $this->response, $out)) {
+				throw new LAMException(_('Error'), 'Could not parse parameter ' . $param . ' from response');
+			}
+			$param_array[$param] = $out[1];
+		}
+		return $param_array;
+	}
+
+	/**
+	 * Verify Yubico OTP against multiple URLs
+	 * Protocol specification 2.0 is used to construct validation requests
+	 *
+	 * @param string $token Yubico OTP
+	 * @param int $use_timestamp 1=>send request with &timestamp=1 to
+	 *        get timestamp and session information
+	 *        in the response
+	 * @param string $sl Sync level in percentage between 0
+	 *        and 100 or "fast" or "secure".
+	 * @param int $timeout Max number of seconds to wait
+	 *        for responses
+	 */
+	public function verify($token, $use_timestamp = null, $sl = null, $timeout = null) {
+		/* Construct parameters string */
+		$ret = $this->parsePasswordOTP($token);
+		if (!$ret) {
+			throw new LAMException(_('Error'), 'Could not parse Yubikey OTP');
+		}
+		$params = array(
+			'id' => $this->clientId,
+			'otp' => $ret['otp'],
+			'nonce' => md5(uniqid(getRandomNumber()))
+		);
+		/* Take care of protocol version 2 parameters */
+		if ($use_timestamp) {
+			$params['timestamp'] = 1;
+		}
+		if ($sl) {
+			$params['sl'] = $sl;
+		}
+		if ($timeout) {
+			$params['timeout'] = $timeout;
+		}
+		ksort($params);
+		$parameters = '';
+		foreach ($params as $p => $v) {
+			$parameters .= "&" . $p . "=" . $v;
+		}
+		$parameters = ltrim($parameters, "&");
+
+		/* Generate signature. */
+		if ($this->clientKey != "") {
+			$signature = base64_encode(hash_hmac('sha1', $parameters, $this->clientKey, true));
+			$signature = preg_replace('/\+/', '%2B', $signature);
+			$parameters .= '&h=' . $signature;
+		}
+
+		/* Generate and prepare request. */
+		$mh = curl_multi_init();
+		$ch = array();
+		$query = $this->url . "?" . $parameters;
+
+		$this->lastquery = $query;
+		logNewMessage(LOG_DEBUG, 'Yubico url: ' . $query);
+
+		$handle = curl_init($query);
+		curl_setopt($handle, CURLOPT_USERAGENT, "LAM Auth Yubico");
+		curl_setopt($handle, CURLOPT_RETURNTRANSFER, 1);
+		if (!$this->httpsVerify) {
+			curl_setopt($handle, CURLOPT_SSL_VERIFYPEER, 0);
+			curl_setopt($handle, CURLOPT_SSL_VERIFYHOST, 0);
+		}
+		curl_setopt($handle, CURLOPT_FAILONERROR, true);
+		/*
+		 * If timeout is set, we better apply it here as well
+		 * in case the validation server fails to follow it.
+		 */
+		if ($timeout) {
+			curl_setopt($handle, CURLOPT_TIMEOUT, $timeout);
+		}
+		// TODO single curl call
+		curl_multi_add_handle($mh, $handle);
+
+		$ch[(int) $handle] = $handle;
+
+		/* Execute and read request. */
+		$this->response = null;
+		$replay = False;
+		$valid = False;
+		do {
+			/* Let curl do its work. */
+			while (($mrc = curl_multi_exec($mh, $active)) == CURLM_CALL_MULTI_PERFORM);
+
+			while ($info = curl_multi_info_read($mh)) {
+				if ($info['result'] == CURLE_OK) {
+
+					/* We have a complete response from one server. */
+
+					$str = curl_multi_getcontent($info['handle']);
+					logNewMessage(LOG_DEBUG, 'Yubico answer: ' . $str);
+					$cinfo = curl_getinfo($info['handle']);
+
+					if (preg_match("/status=([a-zA-Z0-9_]+)/", $str, $out)) {
+						$status = $out[1];
+
+						/*
+						 * There are 3 cases.
+						 *
+						 * 1. OTP or Nonce values doesn't match - ignore
+						 * response.
+						 *
+						 * 2. We have a HMAC key. If signature is invalid -
+						 * ignore response. Return if status=OK/REPLAYED_OTP/BAD_OTP.
+						 *
+						 * 3. Return if status=OK or status=REPLAYED_OTP.
+						 */
+						if (!preg_match("/otp=" . $params['otp'] . "/", $str) || !preg_match("/nonce=" . $params['nonce'] . "/", $str)) {
+							/* Case 1. Ignore response. */
+						}
+						elseif ($this->clientKey != "") {
+							/* Case 2. Verify signature first */
+							$rows = explode("\r\n", trim($str));
+							$response = array();
+							foreach ($rows as $key => $val) {
+								/*
+								 * = is also used in BASE64 encoding so we only replace the first = by # which is not
+								 * used in BASE64
+								 */
+								$val = preg_replace('/=/', '#', $val, 1);
+								$row = explode("#", $val);
+								$response[$row[0]] = $row[1];
+							}
+
+							$parameters = array(
+								'nonce',
+								'otp',
+								'sessioncounter',
+								'sessionuse',
+								'sl',
+								'status',
+								't',
+								'timeout',
+								'timestamp'
+							);
+							sort($parameters);
+							$check = Null;
+							foreach ($parameters as $param) {
+								if (array_key_exists($param, $response)) {
+									if ($check) $check = $check . '&';
+									$check = $check . $param . '=' . $response[$param];
+								}
+							}
+
+							$checksignature = base64_encode(hash_hmac('sha1', utf8_encode($check), $this->clientKey, true));
+
+							if ($response['h'] == $checksignature) {
+								if ($status == 'REPLAYED_OTP') {
+									$this->response = $str;
+									$replay = True;
+								}
+								if ($status == 'OK') {
+									$this->response = $str;
+									$valid = True;
+								}
+								// TODO status BAD_OTP
+							}
+							else {
+								// TODO throw invalid signature exception
+							}
+						}
+						else {
+							/* Case 3. We check the status directly */
+							if ($status == 'REPLAYED_OTP') {
+								$this->response = $str;
+								$replay = True;
+							}
+							if ($status == 'OK') {
+								$this->response = $str;
+								$valid = True;
+							}
+							// TODO status BAD_OTP
+						}
+					}
+					if ($valid || $replay) {
+						/* We have status=OK or status=REPLAYED_OTP, return. */
+						foreach ($ch as $h) {
+							curl_multi_remove_handle($mh, $h);
+							curl_close($h);
+						}
+						curl_multi_close($mh);
+						if ($replay) {
+							throw new LAMException(_('Error'), 'OTP replay detected.');
+						}
+						if ($valid) {
+							return;
+						}
+					}
+
+					curl_multi_remove_handle($mh, $info['handle']);
+					curl_close($info['handle']);
+					unset($ch[(int) $info['handle']]);
+				}
+				curl_multi_select($mh);
+			}
+		}
+		while ($active);
+
+		/*
+		 * Typically this is only reached
+		 * when the timeout is reached and there is no
+		 * OK/REPLAYED_REQUEST answer (think firewall).
+		 */
+
+		foreach ($ch as $h) {
+			curl_multi_remove_handle($mh, $h);
+			curl_close($h);
+		}
+		curl_multi_close($mh);
+
+		throw new LAMException(_('Error'), 'Invalid answer: ' . print_r($this->response, true));
+	}
+
+}
+?>
diff --git a/lam/lib/config.inc b/lam/lib/config.inc
index c254241c..0232cf2e 100644
--- a/lam/lib/config.inc
+++ b/lam/lib/config.inc
@@ -591,6 +591,8 @@ class LAMConfig {
 
 	private $twoFactorAuthentication = TwoFactorProviderService::TWO_FACTOR_NONE;
 	private $twoFactorAuthenticationURL = 'https://localhost';
+	private $twoFactorAuthenticationClientId = null;
+	private $twoFactorAuthenticationSecretKey = null;
 	private $twoFactorAuthenticationInsecure = false;
 	private $twoFactorAuthenticationLabel = null;
 	private $twoFactorAuthenticationOptional = false;
@@ -607,7 +609,7 @@ class LAMConfig {
 		'pwdResetAllowScreenPassword', 'pwdResetForcePasswordChange', 'pwdResetDefaultPasswordOutput',
 		'scriptUserName', 'scriptSSHKey', 'scriptSSHKeyPassword', 'twoFactorAuthentication', 'twoFactorAuthenticationURL',
 		'twoFactorAuthenticationInsecure', 'twoFactorAuthenticationLabel', 'twoFactorAuthenticationOptional',
-		'twoFactorAuthenticationCaption', 'referentialIntegrityOverlay'
+		'twoFactorAuthenticationCaption', 'twoFactorAuthenticationClientId', 'twoFactorAuthenticationSecretKey', 'referentialIntegrityOverlay'
 	);
 
 
@@ -867,6 +869,8 @@ class LAMConfig {
 			if (!in_array("pwdResetDefaultPasswordOutput", $saved)) array_push($file_array, "\n" . "pwdResetDefaultPasswordOutput: " . $this->pwdResetDefaultPasswordOutput . "\n");
 			if (!in_array("twoFactorAuthentication", $saved)) array_push($file_array, "\n" . "twoFactorAuthentication: " . $this->twoFactorAuthentication . "\n");
 			if (!in_array("twoFactorAuthenticationURL", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationURL: " . $this->twoFactorAuthenticationURL . "\n");
+			if (!in_array("twoFactorAuthenticationClientId", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationClientId: " . $this->twoFactorAuthenticationClientId . "\n");
+			if (!in_array("twoFactorAuthenticationSecretKey", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationSecretKey: " . $this->twoFactorAuthenticationSecretKey . "\n");
 			if (!in_array("twoFactorAuthenticationInsecure", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationInsecure: " . $this->twoFactorAuthenticationInsecure . "\n");
 			if (!in_array("twoFactorAuthenticationLabel", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationLabel: " . $this->twoFactorAuthenticationLabel . "\n");
 			if (!in_array("twoFactorAuthenticationOptional", $saved)) array_push($file_array, "\n" . "twoFactorAuthenticationOptional: " . $this->twoFactorAuthenticationOptional . "\n");
@@ -2151,7 +2155,7 @@ class LAMConfig {
 	/**
 	 * Returns the authentication URL.
 	 *
-	 * @return string $twoFactorAuthenticationURL authentication URL
+	 * @return string authentication URL
 	 */
 	public function getTwoFactorAuthenticationURL() {
 		return $this->twoFactorAuthenticationURL;
@@ -2166,10 +2170,46 @@ class LAMConfig {
 		$this->twoFactorAuthenticationURL = $twoFactorAuthenticationURL;
 	}
 
+	/**
+	 * Sets the client id.
+	 *
+	 * @param string $clientId client id
+	 */
+	public function setTwoFactorAuthenticationClientId($clientId) {
+		$this->twoFactorAuthenticationClientId = $clientId;
+	}
+
+	/**
+	 * Returns the client id.
+	 *
+	 * @return string client id
+	 */
+	public function getTwoFactorAuthenticationClientId() {
+		return $this->twoFactorAuthenticationClientId;
+	}
+
+	/**
+	 * Sets the secret key.
+	 *
+	 * @param string $secretKey secret key
+	 */
+	public function setTwoFactorAuthenticationSecretKey($secretKey) {
+		$this->twoFactorAuthenticationSecretKey = $secretKey;
+	}
+
+	/**
+	 * Returns the secret key.
+	 *
+	 * @return string secret key
+	 */
+	public function getTwoFactorAuthenticationSecretKey() {
+		return $this->twoFactorAuthenticationSecretKey;
+	}
+
 	/**
 	 * Returns if SSL certificate verification is turned off.
 	 *
-	 * @return bool $twoFactorAuthenticationInsecure SSL certificate verification is turned off
+	 * @return bool SSL certificate verification is turned off
 	 */
 	public function getTwoFactorAuthenticationInsecure() {
 		return $this->twoFactorAuthenticationInsecure;
@@ -2187,7 +2227,7 @@ class LAMConfig {
 	/**
 	 * Returns the authentication label.
 	 *
-	 * @return string $twoFactorAuthenticationLabel authentication label
+	 * @return string authentication label
 	 */
 	public function getTwoFactorAuthenticationLabel() {
 		return $this->twoFactorAuthenticationLabel;
@@ -2205,7 +2245,7 @@ class LAMConfig {
 	/**
 	 * Returns if 2nd factor is optional.
 	 *
-	 * @return bool $twoFactorAuthenticationOptional 2nd factor is optional
+	 * @return bool 2nd factor is optional
 	 */
 	public function getTwoFactorAuthenticationOptional() {
 		return $this->twoFactorAuthenticationOptional;
@@ -2223,7 +2263,7 @@ class LAMConfig {
 	/**
 	 * Returns the caption HTML.
 	 *
-	 * @return string $twoFactorAuthenticationCaption caption HTML
+	 * @return string caption HTML
 	 */
 	public function getTwoFactorAuthenticationCaption() {
 		return $this->twoFactorAuthenticationCaption;
diff --git a/lam/templates/config/confmain.php b/lam/templates/config/confmain.php
index 3e0e7c8d..c79e62be 100644
--- a/lam/templates/config/confmain.php
+++ b/lam/templates/config/confmain.php
@@ -22,7 +22,7 @@ use \htmlGroup;
 /*
 
   This code is part of LDAP Account Manager (http://www.ldap-account-manager.org/)
-  Copyright (C) 2003 - 2017  Roland Gruber
+  Copyright (C) 2003 - 2018  Roland Gruber
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -460,19 +460,29 @@ if (extension_loaded('curl')) {
 	$twoFactorOptions = array(
 			_('None') => TwoFactorProviderService::TWO_FACTOR_NONE,
 			'privacyIDEA' => TwoFactorProviderService::TWO_FACTOR_PRIVACYIDEA,
+			'YubiKey' => TwoFactorProviderService::TWO_FACTOR_YUBICO,
 	);
 	$twoFactorSelect = new htmlResponsiveSelect('twoFactor', $twoFactorOptions, array($conf->getTwoFactorAuthentication()), _('Provider'), '514');
 	$twoFactorSelect->setHasDescriptiveElements(true);
 	$twoFactorSelect->setTableRowsToHide(array(
-			TwoFactorProviderService::TWO_FACTOR_NONE => array('twoFactorURL', 'twoFactorInsecure', 'twoFactorLabel', 'twoFactorOptional', 'twoFactorCaption')
+			TwoFactorProviderService::TWO_FACTOR_NONE => array('twoFactorURL', 'twoFactorInsecure', 'twoFactorLabel',
+				'twoFactorOptional', 'twoFactorCaption', 'twoFactorClientId', 'twoFactorSecretKey'),
+			TwoFactorProviderService::TWO_FACTOR_PRIVACYIDEA => array('twoFactorClientId', 'twoFactorSecretKey')
 	));
 	$twoFactorSelect->setTableRowsToShow(array(
-			TwoFactorProviderService::TWO_FACTOR_PRIVACYIDEA => array('twoFactorURL', 'twoFactorInsecure', 'twoFactorLabel', 'twoFactorOptional', 'twoFactorCaption')
+			TwoFactorProviderService::TWO_FACTOR_PRIVACYIDEA => array('twoFactorURL', 'twoFactorInsecure', 'twoFactorLabel',
+				'twoFactorOptional', 'twoFactorCaption'),
+			TwoFactorProviderService::TWO_FACTOR_YUBICO => array('twoFactorURL', 'twoFactorInsecure', 'twoFactorLabel',
+				'twoFactorOptional', 'twoFactorCaption', 'twoFactorClientId', 'twoFactorSecretKey'),
 	));
 	$row->add($twoFactorSelect, 12);
 	$twoFactorUrl = new htmlResponsiveInputField(_("Base URL"), 'twoFactorURL', $conf->getTwoFactorAuthenticationURL(), '515');
 	$twoFactorUrl->setRequired(true);
 	$row->add($twoFactorUrl, 12);
+	$twoFactorClientId = new htmlResponsiveInputField(_("Client id"), 'twoFactorClientId', $conf->getTwoFactorAuthenticationClientId(), '524');
+	$row->add($twoFactorClientId, 12);
+	$twoFactorSecretKey = new htmlResponsiveInputField(_("Secret key"), 'twoFactorSecretKey', $conf->getTwoFactorAuthenticationSecretKey(), '525');
+	$row->add($twoFactorSecretKey, 12);
 	$twoFactorLabel = new htmlResponsiveInputField(_("Label"), 'twoFactorLabel', $conf->getTwoFactorAuthenticationLabel(), '517');
 	$row->add($twoFactorLabel, 12);
 	$row->add(new htmlResponsiveInputCheckbox('twoFactorOptional', $conf->getTwoFactorAuthenticationOptional(), _('Optional'), '519'), 12);
@@ -677,6 +687,8 @@ function checkInput() {
 	if (extension_loaded('curl')) {
 		$conf->setTwoFactorAuthentication($_POST['twoFactor']);
 		$conf->setTwoFactorAuthenticationURL($_POST['twoFactorURL']);
+		$conf->setTwoFactorAuthenticationClientId($_POST['twoFactorClientId']);
+		$conf->setTwoFactorAuthenticationSecretKey($_POST['twoFactorSecretKey']);
 		$conf->setTwoFactorAuthenticationInsecure(isset($_POST['twoFactorInsecure']) && ($_POST['twoFactorInsecure'] == 'on'));
 		$conf->setTwoFactorAuthenticationLabel($_POST['twoFactorLabel']);
 		$conf->setTwoFactorAuthenticationOptional(isset($_POST['twoFactorOptional']) && ($_POST['twoFactorOptional'] == 'on'));
diff --git a/lam/tests/lib/LAMConfigTest.php b/lam/tests/lib/LAMConfigTest.php
index d792214d..9a661b2e 100644
--- a/lam/tests/lib/LAMConfigTest.php
+++ b/lam/tests/lib/LAMConfigTest.php
@@ -499,6 +499,94 @@ class LAMConfigTest extends PHPUnit_Framework_TestCase {
 		$this->assertEquals($val, $this->lAMConfig->getHttpAuthentication());
 	}
 
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthentication() and LAMConfig->setTwoFactorAuthentication()
+	 */
+	public function testTwoFactorAuthentication() {
+		$val = '2fid';
+		$this->lAMConfig->setTwoFactorAuthentication($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthentication());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthentication());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationURL() and LAMConfig->setTwoFactorAuthenticationURL()
+	 */
+	public function testTwoFactorAuthenticationURL() {
+		$val = 'http://example.com';
+		$this->lAMConfig->setTwoFactorAuthenticationURL($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationURL());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationURL());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationClientId() and LAMConfig->setTwoFactorAuthenticationClientId()
+	 */
+	public function testTwoFactorAuthenticationClientId() {
+		$val = '1234';
+		$this->lAMConfig->setTwoFactorAuthenticationClientId($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationClientId());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationClientId());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationSecretKey() and LAMConfig->setTwoFactorAuthenticationSecretKey()
+	 */
+	public function testTwoFactorAuthenticationSecretKey() {
+		$val = '3333key';
+		$this->lAMConfig->setTwoFactorAuthenticationSecretKey($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationSecretKey());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationSecretKey());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationInsecure() and LAMConfig->setTwoFactorAuthenticationInsecure()
+	 */
+	public function testTwoFactorAuthenticationInsecure() {
+		$val = true;
+		$this->lAMConfig->setTwoFactorAuthenticationInsecure($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationInsecure());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationInsecure());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationLabel() and LAMConfig->setTwoFactorAuthenticationLabel()
+	 */
+	public function testTwoFactorAuthenticationLabel() {
+		$val = '2falabel';
+		$this->lAMConfig->setTwoFactorAuthenticationLabel($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationLabel());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationLabel());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationOptional() and LAMConfig->setTwoFactorAuthenticationOptional()
+	 */
+	public function testTwoFactorAuthenticationOptional() {
+		$val = true;
+		$this->lAMConfig->setTwoFactorAuthenticationOptional($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationOptional());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationOptional());
+	}
+
+	/**
+	 * Tests LAMConfig->getTwoFactorAuthenticationCaption() and LAMConfig->setTwoFactorAuthenticationCaption()
+	 */
+	public function testTwoFactorAuthenticationCaption() {
+		$val = '2facaption';
+		$this->lAMConfig->setTwoFactorAuthenticationCaption($val);
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationCaption());
+		$this->doSave();
+		$this->assertEquals($val, $this->lAMConfig->getTwoFactorAuthenticationCaption());
+	}
+
 	/**
 	 * Tests LAMConfig->getLamProMailFrom() and LAMConfig->setLamProMailFrom()
 	 */