diff --git a/extensions/yii/authclient/LICENSE.md b/extensions/yii/authclient/LICENSE.md
new file mode 100644
index 0000000..0bb1a8d
--- /dev/null
+++ b/extensions/yii/authclient/LICENSE.md
@@ -0,0 +1,32 @@
+The Yii framework is free software. It is released under the terms of
+the following BSD License.
+
+Copyright © 2008-2013 by Yii Software LLC (http://www.yiisoft.com)
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+ * Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in
+   the documentation and/or other materials provided with the
+   distribution.
+ * Neither the name of Yii Software LLC nor the names of its
+   contributors may be used to endorse or promote products derived
+   from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
diff --git a/extensions/yii/authclient/README.md b/extensions/yii/authclient/README.md
new file mode 100644
index 0000000..b4c57ae
--- /dev/null
+++ b/extensions/yii/authclient/README.md
@@ -0,0 +1,30 @@
+AuthClient Extension for Yii 2
+==============================
+
+This extension adds [OpenID](http://openid.net/), [OAuth](http://oauth.net/) and [OAuth2](http://oauth.net/2/) consumers for the Yii 2 framework.
+
+
+Installation
+------------
+
+The preferred way to install this extension is through [composer](http://getcomposer.org/download/).
+
+Either run
+
+```
+php composer.phar require yiisoft/yii2-authclient "*"
+```
+
+or add
+
+```json
+"yiisoft/yii2-authclient": "*"
+```
+
+to the require section of your composer.json.
+
+
+Usage & Documentation
+---------------------
+
+This extension...
\ No newline at end of file
diff --git a/extensions/yii/authclient/composer.json b/extensions/yii/authclient/composer.json
new file mode 100644
index 0000000..d40889e
--- /dev/null
+++ b/extensions/yii/authclient/composer.json
@@ -0,0 +1,28 @@
+{
+	"name": "yiisoft/yii2-authclient",
+	"description": "External authentication via OAuth and OpenID for the Yii framework",
+	"keywords": ["yii", "OAuth", "OpenID", "auth"],
+	"type": "yii2-extension",
+	"license": "BSD-3-Clause",
+	"support": {
+		"issues": "https://github.com/yiisoft/yii2/issues?state=open",
+		"forum": "http://www.yiiframework.com/forum/",
+		"wiki": "http://www.yiiframework.com/wiki/",
+		"irc": "irc://irc.freenode.net/yii",
+		"source": "https://github.com/yiisoft/yii2"
+	},
+	"authors": [
+		{
+			"name": "Paul Klimov",
+			"email": "klimov.paul@gmail.com"
+		}
+	],
+	"require": {
+		"yiisoft/yii2": "*",
+		"ext-curl": "*"
+	},
+	"autoload": {
+		"psr-0": { "yii\\authclient\\": "" }
+	},
+	"target-dir": "yii/authclient"
+}
diff --git a/extensions/yii/authclient/oauth/BaseClient.php b/extensions/yii/authclient/oauth/BaseClient.php
new file mode 100644
index 0000000..1be63cc
--- /dev/null
+++ b/extensions/yii/authclient/oauth/BaseClient.php
@@ -0,0 +1,504 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth;
+
+use yii\base\Component;
+use yii\base\Exception;
+use yii\base\InvalidParamException;
+use Yii;
+use yii\helpers\Json;
+
+/**
+ * BaseClient is a base class for the OAuth clients.
+ *
+ * @see http://oauth.net/
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+abstract class BaseClient extends Component
+{
+	const CONTENT_TYPE_JSON = 'json'; // JSON format
+	const CONTENT_TYPE_URLENCODED = 'urlencoded'; // urlencoded query string, like name1=value1&name2=value2
+	const CONTENT_TYPE_XML = 'xml'; // XML format
+	const CONTENT_TYPE_AUTO = 'auto'; // attempts to determine format automatically
+
+	/**
+	 * @var string protocol version.
+	 */
+	public $version = '1.0';
+	/**
+	 * @var string URL, which user will be redirected after authentication at the OAuth provider web site.
+	 * Note: this should be absolute URL (with http:// or https:// leading).
+	 * By default current URL will be used.
+	 */
+	private $_returnUrl = '';
+	/**
+	 * @var string API base URL.
+	 */
+	public $apiBaseUrl = '';
+	/**
+	 * @var string authorize URL.
+	 */
+	public $authUrl = '';
+	/**
+	 * @var string auth request scope.
+	 */
+	public $scope = '';
+	/**
+	 * @var array cURL request options. Option values from this field will overwrite corresponding
+	 * values from {@link defaultCurlOptions()}.
+	 */
+	private $_curlOptions = [];
+	/**
+	 * @var Token|array access token instance or its array configuration.
+	 */
+	private $_accessToken = null;
+	/**
+	 * @var signature\BaseMethod|array signature method instance or its array configuration.
+	 */
+	private $_signatureMethod = [];
+
+	/**
+	 * @param string $returnUrl return URL
+	 */
+	public function setReturnUrl($returnUrl)
+	{
+		$this->_returnUrl = $returnUrl;
+	}
+
+	/**
+	 * @return string return URL.
+	 */
+	public function getReturnUrl()
+	{
+		if (empty($this->_returnUrl)) {
+			$this->_returnUrl = $this->defaultReturnUrl();
+		}
+		return $this->_returnUrl;
+	}
+
+	/**
+	 * @param array $curlOptions cURL options.
+	 */
+	public function setCurlOptions(array $curlOptions)
+	{
+		$this->_curlOptions = $curlOptions;
+	}
+
+	/**
+	 * @return array cURL options.
+	 */
+	public function getCurlOptions()
+	{
+		return $this->_curlOptions;
+	}
+
+	/**
+	 * @param array|Token $token
+	 */
+	public function setAccessToken($token)
+	{
+		if (!is_object($token)) {
+			$token = $this->createToken($token);
+		}
+		$this->_accessToken = $token;
+		$this->saveAccessToken($token);
+	}
+
+	/**
+	 * @return Token auth token instance.
+	 */
+	public function getAccessToken()
+	{
+		if (!is_object($this->_accessToken)) {
+			$this->_accessToken = $this->restoreAccessToken();
+		}
+		return $this->_accessToken;
+	}
+
+	/**
+	 * @param array|signature\BaseMethod $signatureMethod signature method instance or its array configuration.
+	 * @throws InvalidParamException on wrong argument.
+	 */
+	public function setSignatureMethod($signatureMethod)
+	{
+		if (!is_object($signatureMethod) && !is_array($signatureMethod)) {
+			throw new InvalidParamException('"'.get_class($this).'::signatureMethod" should be instance of "\yii\autclient\oauth\signature\BaseMethod" or its array configuration. "' . gettype($signatureMethod) . '" has been given.');
+		}
+		$this->_signatureMethod = $signatureMethod;
+	}
+
+	/**
+	 * @return signature\BaseMethod signature method instance.
+	 */
+	public function getSignatureMethod()
+	{
+		if (!is_object($this->_signatureMethod)) {
+			$this->_signatureMethod = $this->createSignatureMethod($this->_signatureMethod);
+		}
+		return $this->_signatureMethod;
+	}
+
+	/**
+	 * Composes default {@link returnUrl} value.
+	 * @return string return URL.
+	 */
+	protected function defaultReturnUrl()
+	{
+		return Yii::$app->getRequest()->getAbsoluteUrl();
+	}
+
+	/**
+	 * Sends HTTP request.
+	 * @param string $method request type.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array response.
+	 * @throws Exception on failure.
+	 */
+	protected function sendRequest($method, $url, array $params = [])
+	{
+		$curlOptions = $this->mergeCurlOptions(
+			$this->defaultCurlOptions(),
+			$this->getCurlOptions(),
+			array(
+				CURLOPT_RETURNTRANSFER => true,
+				CURLOPT_URL => $url,
+			),
+			$this->composeRequestCurlOptions(strtoupper($method), $url, $params)
+		);
+		$curlResource = curl_init();
+		foreach ($curlOptions as $option => $value) {
+			curl_setopt($curlResource, $option, $value);
+		}
+		$response = curl_exec($curlResource);
+		$responseHeaders = curl_getinfo($curlResource);
+
+		// check cURL error
+		$errorNumber = curl_errno($curlResource);
+		$errorMessage = curl_error($curlResource);
+
+		curl_close($curlResource);
+
+		if ($errorNumber > 0) {
+			throw new Exception('Curl error requesting "' .  $url . '": #' . $errorNumber . ' - ' . $errorMessage);
+		}
+		if ($responseHeaders['http_code'] != 200) {
+			throw new Exception('Request failed with code: ' . $responseHeaders['http_code'] . ', message: ' . $response);
+		}
+		return $this->processResponse($response, $this->determineContentTypeByHeaders($responseHeaders));
+	}
+
+	/**
+	 * Merge CUrl options.
+	 * If each options array has an element with the same key value, the latter
+	 * will overwrite the former.
+	 * @param array $options1 options to be merged to.
+	 * @param array $options2 options to be merged from. You can specify additional
+	 * arrays via third argument, fourth argument etc.
+	 * @return array merged options (the original options are not changed.)
+	 */
+	protected function mergeCurlOptions($options1, $options2)
+	{
+		$args = func_get_args();
+		$res = array_shift($args);
+		while (!empty($args)) {
+			$next = array_shift($args);
+			foreach ($next as $k => $v) {
+				$res[$k]=$v;
+			}
+		}
+		return $res;
+	}
+
+	/**
+	 * Returns default cURL options.
+	 * @return array cURL options.
+	 */
+	protected function defaultCurlOptions()
+	{
+		return [
+			CURLOPT_USERAGENT => Yii::$app->name . ' OAuth Client',
+			CURLOPT_CONNECTTIMEOUT => 30,
+			CURLOPT_TIMEOUT => 30,
+			CURLOPT_SSL_VERIFYPEER => false,
+		];
+	}
+
+	/**
+	 * Processes raw response converting it to actual data.
+	 * @param string $rawResponse raw response.
+	 * @param string $contentType response content type.
+	 * @throws Exception on failure.
+	 * @return array actual response.
+	 */
+	protected function processResponse($rawResponse, $contentType = self::CONTENT_TYPE_AUTO)
+	{
+		if (empty($rawResponse)) {
+			return [];
+		}
+		switch ($contentType) {
+			case self::CONTENT_TYPE_AUTO: {
+				$contentType = $this->determineContentTypeByRaw($rawResponse);
+				if ($contentType == self::CONTENT_TYPE_AUTO) {
+					throw new Exception('Unable to determine response content type automatically.');
+				}
+				$response = $this->processResponse($rawResponse, $contentType);
+				break;
+			}
+			case self::CONTENT_TYPE_JSON: {
+				$response = Json::decode($rawResponse, true);
+				if (isset($response['error'])) {
+					throw new Exception('Response error: ' . $response['error']);
+				}
+				break;
+			}
+			case self::CONTENT_TYPE_URLENCODED: {
+				$response = [];
+				parse_url($rawResponse, $response);
+				break;
+			}
+			case self::CONTENT_TYPE_XML: {
+				$response = $this->convertXmlToArray($rawResponse);
+				break;
+			}
+			default: {
+				throw new Exception('Unknown response type "' . $contentType . '".');
+			}
+		}
+		return $response;
+	}
+
+	/**
+	 * Converts XML document to array.
+	 * @param string|\SimpleXMLElement $xml xml to process.
+	 * @return array XML array representation.
+	 */
+	protected function convertXmlToArray($xml)
+	{
+		if (!is_object($xml)) {
+			$xml = simplexml_load_string($xml);
+		}
+		$result = (array)$xml;
+		foreach ($result as $key => $value) {
+			if (is_object($value)) {
+				$result[$key] = $this->convertXmlToArray($value);
+			}
+		}
+		return $result;
+	}
+
+	/**
+	 * Attempts to determine HTTP request content type by headers.
+	 * @param array $headers request headers.
+	 * @return string content type.
+	 */
+	protected function determineContentTypeByHeaders(array $headers)
+	{
+		if (isset($headers['content_type'])) {
+			if (stripos($headers['content_type'], 'json') !== false) {
+				return self::CONTENT_TYPE_JSON;
+			}
+			if (stripos($headers['content_type'], 'urlencoded') !== false) {
+				return self::CONTENT_TYPE_URLENCODED;
+			}
+			if (stripos($headers['content_type'], 'xml') !== false) {
+				return self::CONTENT_TYPE_XML;
+			}
+		}
+		return self::CONTENT_TYPE_AUTO;
+	}
+
+	/**
+	 * Attempts to determine the content type from raw content.
+	 * @param string $rawContent raw response content.
+	 * @return string response type.
+	 */
+	protected function determineContentTypeByRaw($rawContent)
+	{
+		if (preg_match('/^\\{.*\\}$/is', $rawContent)) {
+			return self::CONTENT_TYPE_JSON;
+		}
+		if (preg_match('/^[^=|^&]+=[^=|^&]+(&[^=|^&]+=[^=|^&]+)*$/is', $rawContent)) {
+			return self::CONTENT_TYPE_URLENCODED;
+		}
+		if (preg_match('/^<.*>$/is', $rawContent)) {
+			return self::CONTENT_TYPE_XML;
+		}
+		return self::CONTENT_TYPE_AUTO;
+	}
+
+	/**
+	 * Creates signature method instance from its configuration.
+	 * @param array $signatureMethodConfig signature method configuration.
+	 * @return signature\BaseMethod signature method instance.
+	 */
+	protected function createSignatureMethod(array $signatureMethodConfig)
+	{
+		if (!array_key_exists('class', $signatureMethodConfig)) {
+			$signatureMethodConfig['class'] = signature\HmacSha1::className();
+		}
+		return Yii::createObject($signatureMethodConfig);
+	}
+
+	/**
+	 * Creates token from its configuration.
+	 * @param array $tokenConfig token configuration.
+	 * @return Token token instance.
+	 */
+	protected function createToken(array $tokenConfig = [])
+	{
+		if (!array_key_exists('class', $tokenConfig)) {
+			$tokenConfig['class'] = Token::className();
+		}
+		return Yii::createObject($tokenConfig);
+	}
+
+	/**
+	 * Composes URL from base URL and GET params.
+	 * @param string $url base URL.
+	 * @param array $params GET params.
+	 * @return string composed URL.
+	 */
+	protected function composeUrl($url, array $params = [])
+	{
+		if (strpos($url, '?') === false) {
+			$url .= '?';
+		} else {
+			$url .= '&';
+		}
+		$url .= http_build_query($params, '', '&', PHP_QUERY_RFC3986);
+		return $url;
+	}
+
+	/**
+	 * Saves token as persistent state.
+	 * @param Token $token auth token
+	 * @return static self reference.
+	 */
+	protected function saveAccessToken(Token $token)
+	{
+		return $this->setState('token', $token);
+	}
+
+	/**
+	 * Restores access token.
+	 * @return Token auth token.
+	 */
+	protected function restoreAccessToken()
+	{
+		$token = $this->getState('token');
+		if (is_object($token)) {
+			/* @var $token Token */
+			if ($token->getIsExpired()) {
+				$token = $this->refreshAccessToken($token);
+			}
+		}
+		return $token;
+	}
+
+	/**
+	 * Sets persistent state.
+	 * @param string $key state key.
+	 * @param mixed $value state value
+	 * @return static self reference.
+	 */
+	protected function setState($key, $value)
+	{
+		$session = Yii::$app->getSession();
+		$key = $this->getStateKeyPrefix() . $key;
+		$session->set($key, $value);
+		return $this;
+	}
+
+	/**
+	 * Returns persistent state value.
+	 * @param string $key state key.
+	 * @return mixed state value.
+	 */
+	protected function getState($key)
+	{
+		$session = Yii::$app->getSession();
+		$key = $this->getStateKeyPrefix() . $key;
+		$value = $session->get($key);
+		return $value;
+	}
+
+	/**
+	 * Removes persistent state value.
+	 * @param string $key state key.
+	 * @return boolean success.
+	 */
+	protected function removeState($key)
+	{
+		$session = Yii::$app->getSession();
+		$key = $this->getStateKeyPrefix() . $key;
+		$session->remove($key);
+		return true;
+	}
+
+	/**
+	 * Returns session key prefix, which is used to store internal states.
+	 * @return string session key prefix.
+	 */
+	protected function getStateKeyPrefix()
+	{
+		return get_class($this) . '_' . sha1($this->authUrl) . '_';
+	}
+
+	/**
+	 * Performs request to the OAuth API.
+	 * @param string $apiSubUrl API sub URL, which will be append to [[apiBaseUrl]], or absolute API URL.
+	 * @param string $method request method.
+	 * @param array $params request parameters.
+	 * @return array API response
+	 * @throws Exception on failure.
+	 */
+	public function api($apiSubUrl, $method = 'GET', array $params = [])
+	{
+		if (preg_match('/^https?:\\/\\//is', $apiSubUrl)) {
+			$url = $apiSubUrl;
+		} else {
+			$url = $this->apiBaseUrl . '/' . $apiSubUrl;
+		}
+		$accessToken = $this->getAccessToken();
+		if (!is_object($accessToken) || !$accessToken->getIsValid()) {
+			throw new Exception('Invalid access token.');
+		}
+		return $this->apiInternal($accessToken, $url, $method, $params);
+	}
+
+	/**
+	 * Composes HTTP request CUrl options, which will be merged with the default ones.
+	 * @param string $method request type.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array CUrl options.
+	 * @throws Exception on failure.
+	 */
+	abstract protected function composeRequestCurlOptions($method, $url, array $params);
+
+	/**
+	 * Gets new auth token to replace expired one.
+	 * @param Token $token expired auth token.
+	 * @return Token new auth token.
+	 */
+	abstract public function refreshAccessToken(Token $token);
+
+	/**
+	 * Performs request to the OAuth API.
+	 * @param Token $accessToken actual access token.
+	 * @param string $url absolute API URL.
+	 * @param string $method request method.
+	 * @param array $params request parameters.
+	 * @return array API response.
+	 * @throws Exception on failure.
+	 */
+	abstract protected function apiInternal($accessToken, $url, $method, array $params);
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/Client1.php b/extensions/yii/authclient/oauth/Client1.php
new file mode 100644
index 0000000..5165879
--- /dev/null
+++ b/extensions/yii/authclient/oauth/Client1.php
@@ -0,0 +1,353 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth;
+
+use yii\base\Exception;
+use Yii;
+
+/**
+ * Client1 serves as a client for the OAuth 1/1.0a flow.
+ *
+ * In oder to acquire access token perform following sequence:
+ *
+ * ~~~
+ * use yii\authclient\oauth\Client1;
+ *
+ * $oauthClient = new Client1();
+ * $requestToken = $oauthClient->fetchRequestToken(); // Get request token
+ * $url = $oauthClient->buildAuthUrl($requestToken); // Get authorization URL
+ * Yii::$app->getResponse()->redirect($url); // Redirect to authorization URL
+ * // After user returns at our site:
+ * $accessToken = $oauthClient->fetchAccessToken($requestToken); // Upgrade to access token
+ * ~~~
+ *
+ * @see http://oauth.net/
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class Client1 extends BaseClient
+{
+	/**
+	 * @var string protocol version.
+	 */
+	public $version = '1.0';
+	/**
+	 * @var string OAuth consumer key.
+	 */
+	public $consumerKey = '';
+	/**
+	 * @var string OAuth consumer secret.
+	 */
+	public $consumerSecret = '';
+	/**
+	 * @var string OAuth request token URL.
+	 */
+	public $requestTokenUrl = '';
+	/**
+	 * @var string request token HTTP method.
+	 */
+	public $requestTokenMethod = 'GET';
+	/**
+	 * @var string OAuth access token URL.
+	 */
+	public $accessTokenUrl = '';
+	/**
+	 * @var string access token HTTP method.
+	 */
+	public $accessTokenMethod = 'GET';
+
+	/**
+	 * Fetches the OAuth request token.
+	 * @param array $params additional request params.
+	 * @return Token request token.
+	 */
+	public function fetchRequestToken(array $params = [])
+	{
+		$this->removeState('token');
+		$defaultParams = [
+			'oauth_consumer_key' => $this->consumerKey,
+			'oauth_callback' => $this->getReturnUrl(),
+			//'xoauth_displayname' => Yii::$app->name,
+		];
+		if (!empty($this->scope)) {
+			$defaultParams['scope'] = $this->scope;
+		}
+		$response = $this->sendSignedRequest($this->requestTokenMethod, $this->requestTokenUrl, array_merge($defaultParams, $params));
+		$token = $this->createToken([
+			'params' => $response
+		]);
+		$this->setState('requestToken', $token);
+		return $token;
+	}
+
+	/**
+	 * Composes user authorization URL.
+	 * @param Token $requestToken OAuth request token.
+	 * @param array $params additional request params.
+	 * @return string authorize URL
+	 * @throws Exception on failure.
+	 */
+	public function buildAuthUrl(Token $requestToken = null, array $params = [])
+	{
+		if (!is_object($requestToken)) {
+			$requestToken = $this->getState('requestToken');
+			if (!is_object($requestToken)) {
+				throw new Exception('Request token is required to build authorize URL!');
+			}
+		}
+		$params['oauth_token'] = $requestToken->getToken();
+		return $this->composeUrl($this->authUrl, $params);
+	}
+
+	/**
+	 * Fetches OAuth access token.
+	 * @param Token $requestToken OAuth request token.
+	 * @param string $oauthVerifier OAuth verifier.
+	 * @param array $params additional request params.
+	 * @return Token OAuth access token.
+	 * @throws Exception on failure.
+	 */
+	public function fetchAccessToken(Token $requestToken = null, $oauthVerifier = null, array $params = [])
+	{
+		if (!is_object($requestToken)) {
+			$requestToken = $this->getState('requestToken');
+			if (!is_object($requestToken)) {
+				throw new Exception('Request token is required to fetch access token!');
+			}
+		}
+		$this->removeState('requestToken');
+		$defaultParams = [
+			'oauth_consumer_key' => $this->consumerKey,
+			'oauth_token' => $requestToken->getToken()
+		];
+		if ($oauthVerifier === null) {
+			if (isset($_REQUEST['oauth_verifier'])) {
+				$oauthVerifier = $_REQUEST['oauth_verifier'];
+			}
+		}
+		if (!empty($oauthVerifier)) {
+			$defaultParams['oauth_verifier'] = $oauthVerifier;
+		}
+		$response = $this->sendSignedRequest($this->accessTokenMethod, $this->accessTokenUrl, array_merge($defaultParams, $params));
+
+		$token = $this->createToken([
+			'params' => $response
+		]);
+		$this->setAccessToken($token);
+		return $token;
+	}
+
+	/**
+	 * Sends HTTP request, signed by {@link signatureMethod}.
+	 * @param string $method request type.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array response.
+	 */
+	protected function sendSignedRequest($method, $url, array $params = [])
+	{
+		$params = array_merge($params, $this->generateCommonRequestParams());
+		$params = $this->signRequest($method, $url, $params);
+		return $this->sendRequest($method, $url, $params);
+	}
+
+	/**
+	 * Composes HTTP request CUrl options, which will be merged with the default ones.
+	 * @param string $method request type.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array CUrl options.
+	 * @throws Exception on failure.
+	 */
+	protected function composeRequestCurlOptions($method, $url, array $params)
+	{
+		$curlOptions = [];
+		switch ($method) {
+			case 'GET': {
+				$curlOptions[CURLOPT_URL] = $this->composeUrl($url, $params);
+				break;
+			}
+			case 'POST': {
+				$curlOptions[CURLOPT_POST] = true;
+				if (!empty($params)){
+					$curlOptions[CURLOPT_POSTFIELDS] = $params;
+				}
+				$authorizationHeader = $this->composeAuthorizationHeader($params);
+				if (!empty($authorizationHeader)/* && $this->curlAuthHeader*/) {
+					$curlOptions[CURLOPT_HTTPHEADER] = ['Content-Type: application/atom+xml', $authorizationHeader];
+				}
+				break;
+			}
+			case 'HEAD':
+			case 'PUT':
+			case 'DELETE': {
+				$curlOptions[CURLOPT_CUSTOMREQUEST] = $method;
+				if (!empty($params)) {
+					$curlOptions[CURLOPT_URL] = $this->composeUrl($url, $params);
+				}
+				break;
+			}
+			default: {
+				throw new Exception("Unknown request method '{$method}'.");
+			}
+		}
+		return $curlOptions;
+	}
+
+	/**
+	 * Performs request to the OAuth API.
+	 * @param Token $accessToken actual access token.
+	 * @param string $url absolute API URL.
+	 * @param string $method request method.
+	 * @param array $params request parameters.
+	 * @return array API response.
+	 * @throws Exception on failure.
+	 */
+	protected function apiInternal($accessToken, $url, $method, array $params)
+	{
+		$params['oauth_consumer_key'] = $this->consumerKey;
+		$params['oauth_token'] = $accessToken->getToken();
+		$response = $this->sendSignedRequest($method, $url, $params);
+		return $response;
+	}
+
+	/**
+	 * Gets new auth token to replace expired one.
+	 * @param Token $token expired auth token.
+	 * @return Token new auth token.
+	 */
+	public function refreshAccessToken(Token $token)
+	{
+		// @todo
+		return null;
+	}
+
+	/**
+	 * Composes default {@link returnUrl} value.
+	 * @return string return URL.
+	 */
+	protected function defaultReturnUrl()
+	{
+		$params = $_GET;
+		unset($params['oauth_token']);
+		return Yii::$app->getUrlManager()->createAbsoluteUrl(Yii::$app->controller->getRoute(), $params);
+	}
+
+	/**
+	 * Generates nonce value.
+	 * @return string nonce value.
+	 */
+	protected function generateNonce()
+	{
+		return md5(microtime() . mt_rand());
+	}
+
+	/**
+	 * Generates timestamp.
+	 * @return integer timestamp.
+	 */
+	protected function generateTimestamp()
+	{
+		return time();
+	}
+
+	/**
+	 * Generate common request params like version, timestamp etc.
+	 * @return array common request params.
+	 */
+	protected function generateCommonRequestParams()
+	{
+		$params = [
+			'oauth_version' => $this->version,
+			'oauth_nonce' => $this->generateNonce(),
+			'oauth_timestamp' => $this->generateTimestamp(),
+		];
+		return $params;
+	}
+
+	/**
+	 * Sign request with {@link signatureMethod}.
+	 * @param string $method request method.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array signed request params.
+	 */
+	protected function signRequest($method, $url, array $params)
+	{
+		$signatureMethod = $this->getSignatureMethod();
+		$params['oauth_signature_method'] = $signatureMethod->getName();
+		$signatureBaseString = $this->composeSignatureBaseString($method, $url, $params);
+		$signatureKey = $this->composeSignatureKey();
+		$params['oauth_signature'] = $signatureMethod->generateSignature($signatureBaseString, $signatureKey);
+		return $params;
+	}
+
+	/**
+	 * Creates signature base string, which will be signed by {@link signatureMethod}.
+	 * @param string $method request method.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return string base signature string.
+	 */
+	protected function composeSignatureBaseString($method, $url, array $params)
+	{
+		unset($params['oauth_signature']);
+		$parts = [
+			strtoupper($method),
+			$url,
+			http_build_query($params, '', '&', PHP_QUERY_RFC3986)
+		];
+		$parts = array_map('rawurlencode', $parts);
+		return implode('&', $parts);
+	}
+
+	/**
+	 * Composes request signature key.
+	 * @return string signature key.
+	 */
+	protected function composeSignatureKey()
+	{
+		$signatureKeyParts = [
+			$this->consumerSecret
+		];
+		$accessToken = $this->getAccessToken();
+		if (is_object($accessToken)) {
+			$signatureKeyParts[] = $accessToken->getTokenSecret();
+		} else {
+			$signatureKeyParts[] = '';
+		}
+		$signatureKeyParts = array_map('rawurlencode', $signatureKeyParts);
+		return implode('&', $signatureKeyParts);
+	}
+
+	/**
+	 * Composes authorization header content.
+	 * @param array $params request params.
+	 * @param string $realm authorization realm.
+	 * @return string authorization header content.
+	 */
+	protected function composeAuthorizationHeader(array $params, $realm = '')
+	{
+		$header = 'Authorization: OAuth';
+		$headerParams = [];
+		if (!empty($realm)) {
+			$headerParams[] = 'realm="' . rawurlencode($realm) . '"';
+		}
+		foreach ($params as $key => $value) {
+			if (substr($key, 0, 5) != 'oauth') {
+				continue;
+			}
+			$headerParams[] = rawurlencode($key) . '="' . rawurlencode($value) . '"';
+		}
+		if (!empty($headerParams)) {
+			$header .= ' ' . implode(', ', $headerParams);
+		}
+		return $header;
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/Client2.php b/extensions/yii/authclient/oauth/Client2.php
new file mode 100644
index 0000000..128fad5
--- /dev/null
+++ b/extensions/yii/authclient/oauth/Client2.php
@@ -0,0 +1,184 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth;
+
+use Yii;
+use yii\base\Exception;
+
+/**
+ * Client2 serves as a client for the OAuth 2 flow.
+ *
+ * In oder to acquire access token perform following sequence:
+ *
+ * ~~~
+ * use yii\authclient\oauth\Client2;
+ *
+ * $oauthClient = new Client2();
+ * $url = $oauthClient->buildAuthUrl(); // Build authorization URL
+ * Yii::$app->getResponse()->redirect($url); // Redirect to authorization URL.
+ * // After user returns at our site:
+ * $code = $_GET['code'];
+ * $accessToken = $oauthClient->fetchAccessToken($code); // Get access token
+ * ~~~
+ *
+ * @see http://oauth.net/2/
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class Client2 extends BaseClient
+{
+	/**
+	 * @var string protocol version.
+	 */
+	public $version = '2.0';
+	/**
+	 * @var string OAuth client ID.
+	 */
+	public $clientId = '';
+	/**
+	 * @var string OAuth client secret.
+	 */
+	public $clientSecret = '';
+	/**
+	 * @var string token request URL endpoint.
+	 */
+	public $tokenUrl = '';
+
+	/**
+	 * Composes user authorization URL.
+	 * @param array $params additional auth GET params.
+	 * @return string authorization URL.
+	 */
+	public function buildAuthUrl(array $params = [])
+	{
+		$defaultParams = [
+			'client_id' => $this->clientId,
+			'response_type' => 'code',
+			'redirect_uri' => $this->getReturnUrl(),
+			'xoauth_displayname' => Yii::$app->name,
+		];
+		if (!empty($this->scope)) {
+			$defaultParams['scope'] = $this->scope;
+		}
+		return $this->composeUrl($this->authUrl, array_merge($defaultParams, $params));
+	}
+
+	/**
+	 * Fetches access token from authorization code.
+	 * @param string $authCode authorization code, usually comes at $_GET['code'].
+	 * @param array $params additional request params.
+	 * @return Token access token.
+	 */
+	public function fetchAccessToken($authCode, array $params = [])
+	{
+		$defaultParams = [
+			'client_id' => $this->clientId,
+			'client_secret' => $this->clientSecret,
+			'code' => $authCode,
+			'grant_type' => 'authorization_code',
+			'redirect_uri' => $this->getReturnUrl(),
+		];
+		$response = $this->sendRequest('POST', $this->tokenUrl, array_merge($defaultParams, $params));
+		$token = $this->createToken(['params' => $response]);
+		$this->setAccessToken($token);
+		return $token;
+	}
+
+	/**
+	 * Composes HTTP request CUrl options, which will be merged with the default ones.
+	 * @param string $method request type.
+	 * @param string $url request URL.
+	 * @param array $params request params.
+	 * @return array CUrl options.
+	 * @throws Exception on failure.
+	 */
+	protected function composeRequestCurlOptions($method, $url, array $params)
+	{
+		$curlOptions = [];
+		switch ($method) {
+			case 'GET': {
+				$curlOptions[CURLOPT_URL] = $this->composeUrl($url, $params);
+				break;
+			}
+			case 'POST': {
+				$curlOptions[CURLOPT_POST] = true;
+				$curlOptions[CURLOPT_HTTPHEADER] = ['Content-type: application/x-www-form-urlencoded'];
+				$curlOptions[CURLOPT_POSTFIELDS] = http_build_query($params, '', '&', PHP_QUERY_RFC3986);
+				break;
+			}
+			case 'HEAD':
+			case 'PUT':
+			case 'DELETE': {
+				$curlOptions[CURLOPT_CUSTOMREQUEST] = $method;
+				if (!empty($params)) {
+					$curlOptions[CURLOPT_URL] = $this->composeUrl($url, $params);
+				}
+				break;
+			}
+			default: {
+				throw new Exception("Unknown request method '{$method}'.");
+			}
+		}
+		return $curlOptions;
+	}
+
+	/**
+	 * Performs request to the OAuth API.
+	 * @param Token $accessToken actual access token.
+	 * @param string $url absolute API URL.
+	 * @param string $method request method.
+	 * @param array $params request parameters.
+	 * @return array API response.
+	 * @throws Exception on failure.
+	 */
+	protected function apiInternal($accessToken, $url, $method, array $params)
+	{
+		$params['access_token'] = $accessToken->getToken();
+		return $this->sendRequest($method, $url, $params);
+	}
+
+	/**
+	 * Gets new auth token to replace expired one.
+	 * @param Token $token expired auth token.
+	 * @return Token new auth token.
+	 */
+	public function refreshAccessToken(Token $token)
+	{
+		$params = [
+			'client_id' => $this->clientId,
+			'client_secret' => $this->clientSecret,
+			'grant_type' => 'refresh_token'
+		];
+		$params = array_merge($token->getParams(), $params);
+		$response = $this->sendRequest('POST', $this->tokenUrl, $params);
+		return $response;
+	}
+
+	/**
+	 * Composes default {@link returnUrl} value.
+	 * @return string return URL.
+	 */
+	protected function defaultReturnUrl()
+	{
+		$params = $_GET;
+		unset($params['code']);
+		return Yii::$app->getUrlManager()->createAbsoluteUrl(Yii::$app->controller->getRoute(), $params);
+	}
+
+	/**
+	 * Creates token from its configuration.
+	 * @param array $tokenConfig token configuration.
+	 * @return Token token instance.
+	 */
+	protected function createToken(array $tokenConfig = [])
+	{
+		$tokenConfig['tokenParamKey'] = 'access_token';
+		return parent::createToken($tokenConfig);
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/Token.php b/extensions/yii/authclient/oauth/Token.php
new file mode 100644
index 0000000..16e6d1e
--- /dev/null
+++ b/extensions/yii/authclient/oauth/Token.php
@@ -0,0 +1,186 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth;
+
+use yii\base\Object;
+
+/**
+ * Token represents OAuth token.
+ *
+ * @property array $params token parameters.
+ * @property string $token token value.
+ * @property string $tokenSecret token secret value.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class Token extends Object
+{
+	/**
+	 * @var string key in {@link _params} array, which stores token key.
+	 */
+	public $tokenParamKey = 'oauth_token';
+	/**
+	 * @var string key in {@link _params} array, which stores token secret key.
+	 */
+	public $tokenSecretParamKey = 'oauth_token_secret';
+	/**
+	 * @var string key in {@link _params} array, which stores token expiration duration.
+	 * If not set will attempt to fetch its value automatically.
+	 */
+	private $_expireDurationParamKey;
+	/**
+	 * @var array token parameters.
+	 */
+	private $_params = [];
+	/**
+	 * @var integer object creation timestamp.
+	 */
+	public $createTimestamp;
+
+	public function init()
+	{
+		if ($this->createTimestamp === null) {
+			$this->createTimestamp = time();
+		}
+	}
+
+	/**
+	 * @param string $expireDurationParamKey expire duration param key.
+	 */
+	public function setExpireDurationParamKey($expireDurationParamKey) {
+		$this->_expireDurationParamKey = $expireDurationParamKey;
+	}
+
+	/**
+	 * @return string expire duration param key.
+	 */
+	public function getExpireDurationParamKey() {
+		if ($this->_expireDurationParamKey === null) {
+			$this->_expireDurationParamKey = $this->defaultExpireDurationParamKey();
+		}
+		return $this->_expireDurationParamKey;
+	}
+
+	/**
+	 * @return array
+	 */
+	public function getParams() {
+		return $this->_params;
+	}
+
+	/**
+	 * @param array $params
+	 */
+	public function setParams(array $params) {
+		$this->_params = $params;
+	}
+
+	/**
+	 * Sets param by name.
+	 * @param string $name param name.
+	 * @param mixed $value param value,
+	 */
+	public function setParam($name, $value) {
+		$this->_params[$name] = $value;
+	}
+
+	/**
+	 * Returns param by name.
+	 * @param string $name param name.
+	 * @return mixed param value.
+	 */
+	public function getParam($name) {
+		return isset($this->_params[$name]) ? $this->_params[$name] : null;
+	}
+
+	/**
+	 * Sets token value.
+	 * @param string $token token value.
+	 * @return static self reference.
+	 */
+	public function setToken($token) {
+		$this->setParam($this->tokenParamKey, $token);
+	}
+
+	/**
+	 * Returns token value.
+	 * @return string token value.
+	 */
+	public function getToken() {
+		return $this->getParam($this->tokenParamKey);
+	}
+
+	/**
+	 * Sets the token secret value.
+	 * @param string $tokenSecret token secret.
+	 */
+	public function setTokenSecret($tokenSecret) {
+		$this->setParam($this->tokenSecretParamKey, $tokenSecret);
+	}
+
+	/**
+	 * Returns the token secret value.
+	 * @return string token secret value.
+	 */
+	public function getTokenSecret() {
+		return $this->getParam($this->tokenSecretParamKey);
+	}
+
+	/**
+	 * Sets token expire duration.
+	 * @param string $expireDuration token expiration duration.
+	 */
+	public function setExpireDuration($expireDuration) {
+		$this->setParam($this->getExpireDurationParamKey(), $expireDuration);
+	}
+
+	/**
+	 * Returns the token expiration duration.
+	 * @return integer token expiration duration.
+	 */
+	public function getExpireDuration() {
+		return $this->getParam($this->getExpireDurationParamKey());
+	}
+
+	/**
+	 * Fetches default expire duration param key.
+	 * @return string expire duration param key.
+	 */
+	protected function defaultExpireDurationParamKey() {
+		$expireDurationParamKey = 'expires_in';
+		foreach ($this->getParams() as $name => $value) {
+			if (strpos($name, 'expir') !== false) {
+				$expireDurationParamKey = $name;
+				break;
+			}
+		}
+		return $expireDurationParamKey;
+	}
+
+	/**
+	 * Checks if token has expired.
+	 * @return boolean is token expired.
+	 */
+	public function getIsExpired() {
+		$expirationDuration = $this->getExpireDuration();
+		if (empty($expirationDuration)) {
+			return false;
+		}
+		return (time() >= ($this->createTimestamp + $expirationDuration));
+	}
+
+	/**
+	 * Checks if token is valid.
+	 * @return boolean is token valid.
+	 */
+	public function getIsValid() {
+		$token = $this->getToken();
+		return (!empty($token) && !$this->getIsExpired());
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/signature/BaseMethod.php b/extensions/yii/authclient/oauth/signature/BaseMethod.php
new file mode 100644
index 0000000..1fcefdf
--- /dev/null
+++ b/extensions/yii/authclient/oauth/signature/BaseMethod.php
@@ -0,0 +1,51 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth\signature;
+
+use yii\base\Object;
+
+/**
+ * BaseMethod is a base class for the OAuth signature methods.
+ *
+ * @property string $name method canonical name. This property is read-only.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+abstract class BaseMethod extends Object
+{
+	/**
+	 * Return the canonical name of the Signature Method.
+	 * @return string method name.
+	 */
+	abstract public function getName();
+
+	/**
+	 * Generates OAuth request signature.
+	 * @param string $baseString signature base string.
+	 * @param string $key signature key.
+	 * @return string signature string.
+	 */
+	abstract public function generateSignature($baseString, $key);
+
+	/**
+	 * Verifies given OAuth request.
+	 * @param string $signature signature to be verified.
+	 * @param string $baseString signature base string.
+	 * @param string $key signature key.
+	 * @return boolean success.
+	 */
+	public function verify($signature, $baseString, $key)
+	{
+		$expectedSignature = $this->generateSignature($baseString, $key);
+		if (empty($signature) || empty($expectedSignature)) {
+			return false;
+		}
+		return (strcmp($expectedSignature, $signature) === 0);
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/signature/HmacSha1.php b/extensions/yii/authclient/oauth/signature/HmacSha1.php
new file mode 100644
index 0000000..3a7f223
--- /dev/null
+++ b/extensions/yii/authclient/oauth/signature/HmacSha1.php
@@ -0,0 +1,47 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth\signature;
+
+use yii\base\NotSupportedException;
+
+/**
+ * HmacSha1 represents 'HMAC-SHA1' signature method.
+ *
+ * Note: This class require PHP "Hash" extension({@link http://php.net/manual/en/book.hash.php}).
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class HmacSha1 extends BaseMethod
+{
+	/**
+	 * @inheritdoc
+	 */
+	public function init()
+	{
+		if (!function_exists('hash_hmac')) {
+			throw new NotSupportedException('PHP "Hash" extension is required.');
+		}
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function getName()
+	{
+		return 'HMAC-SHA1';
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function generateSignature($baseString, $key)
+	{
+		return base64_encode(hash_hmac('sha1', $baseString, $key, true));
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/signature/PlainText.php b/extensions/yii/authclient/oauth/signature/PlainText.php
new file mode 100644
index 0000000..1140814
--- /dev/null
+++ b/extensions/yii/authclient/oauth/signature/PlainText.php
@@ -0,0 +1,33 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth\signature;
+
+/**
+ * PlainText represents 'PLAINTEXT' signature method.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class PlainText extends BaseMethod
+{
+	/**
+	 * @inheritdoc
+	 */
+	public function getName()
+	{
+		return 'PLAINTEXT';
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function generateSignature($baseString, $key)
+	{
+		return $key;
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/oauth/signature/RsaSha1.php b/extensions/yii/authclient/oauth/signature/RsaSha1.php
new file mode 100644
index 0000000..e140fd5
--- /dev/null
+++ b/extensions/yii/authclient/oauth/signature/RsaSha1.php
@@ -0,0 +1,168 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\oauth\signature;
+
+use yii\base\InvalidConfigException;
+use yii\base\NotSupportedException;
+
+/**
+ * RsaSha1 represents 'RSA-SHA1' signature method.
+ *
+ * Note: This class require PHP "OpenSSL" extension({@link http://php.net/manual/en/book.openssl.php}).
+ *
+ * @property string $privateCertificate OpenSSL private key certificate content.
+ * @property string $publicCertificate OpenSSL public key certificate content.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class RsaSha1 extends BaseMethod
+{
+	/**
+	 * @var string OpenSSL private key certificate content.
+	 * This value can be fetched from file specified by {@link privateCertificateFile}.
+	 */
+	protected $_privateCertificate;
+	/**
+	 * @var string OpenSSL public key certificate content.
+	 * This value can be fetched from file specified by {@link publicCertificateFile}.
+	 */
+	protected $_publicCertificate;
+	/**
+	 * @var string path to the file, which holds private key certificate.
+	 */
+	public $privateCertificateFile = '';
+	/**
+	 * @var string path to the file, which holds public key certificate.
+	 */
+	public $publicCertificateFile = '';
+
+	/**
+	 * @inheritdoc
+	 */
+	public function init()
+	{
+		if (!function_exists('openssl_sign')) {
+			throw new NotSupportedException('PHP "OpenSSL" extension is required.');
+		}
+	}
+
+	/**
+	 * @param string $publicCertificate public key certificate content.
+	 */
+	public function setPublicCertificate($publicCertificate)
+	{
+		$this->_publicCertificate = $publicCertificate;
+	}
+
+	/**
+	 * @return string public key certificate content.
+	 */
+	public function getPublicCertificate()
+	{
+		if ($this->_publicCertificate === null) {
+			$this->_publicCertificate = $this->initPublicCertificate();
+		}
+		return $this->_publicCertificate;
+	}
+
+	/**
+	 * @param string $privateCertificate private key certificate content.
+	 */
+	public function setPrivateCertificate($privateCertificate)
+	{
+		$this->_privateCertificate = $privateCertificate;
+	}
+
+	/**
+	 * @return string private key certificate content.
+	 */
+	public function getPrivateCertificate()
+	{
+		if ($this->_privateCertificate === null) {
+			$this->_privateCertificate = $this->initPrivateCertificate();
+		}
+		return $this->_privateCertificate;
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function getName()
+	{
+		return 'RSA-SHA1';
+	}
+
+	/**
+	 * Creates initial value for {@link publicCertificate}.
+	 * This method will attempt to fetch the certificate value from {@link publicCertificateFile} file.
+	 * @throws InvalidConfigException on failure.
+	 * @return string public certificate content.
+	 */
+	protected function initPublicCertificate()
+	{
+		if (!empty($this->publicCertificateFile)) {
+			if (!file_exists($this->publicCertificateFile)) {
+				throw new InvalidConfigException("Public certificate file '{$this->publicCertificateFile}' does not exist!");
+			}
+			return file_get_contents($this->publicCertificateFile);
+		} else {
+			return '';
+		}
+	}
+
+	/**
+	 * Creates initial value for {@link privateCertificate}.
+	 * This method will attempt to fetch the certificate value from {@link privateCertificateFile} file.
+	 * @throws InvalidConfigException on failure.
+	 * @return string private certificate content.
+	 */
+	protected function initPrivateCertificate()
+	{
+		if (!empty($this->privateCertificateFile)) {
+			if (!file_exists($this->privateCertificateFile)) {
+				throw new InvalidConfigException("Private certificate file '{$this->privateCertificateFile}' does not exist!");
+			}
+			return file_get_contents($this->privateCertificateFile);
+		} else {
+			return '';
+		}
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function generateSignature($baseString, $key)
+	{
+		$privateCertificateContent = $this->getPrivateCertificate();
+		// Pull the private key ID from the certificate
+		$privateKeyId = openssl_pkey_get_private($privateCertificateContent);
+		// Sign using the key
+		openssl_sign($baseString, $signature, $privateKeyId);
+		// Release the key resource
+		openssl_free_key($privateKeyId);
+		return base64_encode($signature);
+	}
+
+	/**
+	 * @inheritdoc
+	 */
+	public function verify($signature, $baseString, $key)
+	{
+		$decodedSignature = base64_decode($signature);
+		// Fetch the public key cert based on the request
+		$publicCertificate = $this->getPublicCertificate();
+		// Pull the public key ID from the certificate
+		$publicKeyId = openssl_pkey_get_public($publicCertificate);
+		// Check the computed signature against the one passed in the query
+		$verificationResult = openssl_verify($baseString, $decodedSignature, $publicKeyId);
+		// Release the key resource
+		openssl_free_key($publicKeyId);
+		return ($verificationResult == 1);
+	}
+}
\ No newline at end of file
diff --git a/extensions/yii/authclient/openid/Client.php b/extensions/yii/authclient/openid/Client.php
new file mode 100644
index 0000000..709259d
--- /dev/null
+++ b/extensions/yii/authclient/openid/Client.php
@@ -0,0 +1,23 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\authclient\openid;
+
+use yii\base\Component;
+
+/**
+ * Class Client
+ *
+ * @see http://openid.net/
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class Client extends Component
+{
+
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/TestCase.php b/tests/unit/extensions/authclient/TestCase.php
new file mode 100644
index 0000000..30fe5de
--- /dev/null
+++ b/tests/unit/extensions/authclient/TestCase.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace yiiunit\extensions\authclient;
+
+use yii\helpers\FileHelper;
+use Yii;
+
+/**
+ * TestCase for "authclient" extension.
+ */
+class TestCase extends \yiiunit\TestCase
+{
+	public static function setUpBeforeClass()
+	{
+		static::loadClassMap();
+	}
+
+	/**
+	 * Adds sphinx extension files to [[Yii::$classPath]],
+	 * avoiding the necessity of usage Composer autoloader.
+	 */
+	protected static function loadClassMap()
+	{
+		$baseNameSpace = 'yii/authclient';
+		$basePath = realpath(__DIR__. '/../../../../extensions/yii/authclient');
+		$files = FileHelper::findFiles($basePath);
+		foreach ($files as $file) {
+			$classRelativePath = str_replace($basePath, '', $file);
+			$classFullName = str_replace(['/', '.php'], ['\\', ''], $baseNameSpace . $classRelativePath);
+			Yii::$classMap[$classFullName] = $file;
+		}
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/BaseClientTest.php b/tests/unit/extensions/authclient/oauth/BaseClientTest.php
new file mode 100644
index 0000000..e5085e7
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/BaseClientTest.php
@@ -0,0 +1,251 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth;
+
+use yii\authclient\oauth\signature\PlainText;
+use yii\authclient\oauth\Token;
+use yiiunit\extensions\authclient\TestCase;
+use yii\authclient\oauth\BaseClient;
+
+class BaseClientTest extends TestCase
+{
+	/**
+	 * Creates test OAuth client instance.
+	 * @return BaseClient oauth client.
+	 */
+	protected function createOAuthClient()
+	{
+		$oauthClient = $this->getMock(BaseClient::className(), ['setState', 'getState', 'composeRequestCurlOptions', 'refreshAccessToken', 'apiInternal']);
+		$oauthClient->expects($this->any())->method('setState')->will($this->returnValue($oauthClient));
+		$oauthClient->expects($this->any())->method('getState')->will($this->returnValue(null));
+		return $oauthClient;
+	}
+
+	/**
+	 * Invokes the OAuth client method even if it is protected.
+	 * @param BaseClient $oauthClient OAuth client instance.
+	 * @param string $methodName name of the method to be invoked.
+	 * @param array $arguments method arguments.
+	 * @return mixed method invoke result.
+	 */
+	protected function invokeOAuthClientMethod($oauthClient, $methodName, array $arguments = [])
+	{
+		$classReflection = new \ReflectionClass(get_class($oauthClient));
+		$methodReflection = $classReflection->getMethod($methodName);
+		$methodReflection->setAccessible(true);
+		$result = $methodReflection->invokeArgs($oauthClient, $arguments);
+		$methodReflection->setAccessible(false);
+		return $result;
+	}
+
+	// Tests :
+
+	public function testSetGet()
+	{
+		$oauthClient = $this->createOAuthClient();
+
+		$returnUrl = 'http://test.return.url';
+		$oauthClient->setReturnUrl($returnUrl);
+		$this->assertEquals($returnUrl, $oauthClient->getReturnUrl(), 'Unable to setup return URL!');
+
+		$curlOptions = [
+			'option1' => 'value1',
+			'option2' => 'value2',
+		];
+		$oauthClient->setCurlOptions($curlOptions);
+		$this->assertEquals($curlOptions, $oauthClient->getCurlOptions(), 'Unable to setup cURL options!');
+	}
+
+	public function testSetupComponents()
+	{
+		$oauthClient = $this->createOAuthClient();
+
+		$oauthToken = new Token();
+		$oauthClient->setAccessToken($oauthToken);
+		$this->assertEquals($oauthToken, $oauthClient->getAccessToken(), 'Unable to setup token!');
+
+		$oauthSignatureMethod = new PlainText();
+		$oauthClient->setSignatureMethod($oauthSignatureMethod);
+		$this->assertEquals($oauthSignatureMethod, $oauthClient->getSignatureMethod(), 'Unable to setup signature method!');
+	}
+
+	/**
+	 * @depends testSetupComponents
+	 */
+	public function testSetupComponentsByConfig()
+	{
+		$oauthClient = $this->createOAuthClient();
+
+		$oauthToken = [
+			'token' => 'test_token',
+			'tokenSecret' => 'test_token_secret',
+		];
+		$oauthClient->setAccessToken($oauthToken);
+		$this->assertEquals($oauthToken['token'], $oauthClient->getAccessToken()->getToken(), 'Unable to setup token as config!');
+
+		$oauthSignatureMethod = [
+			'class' => 'yii\authclient\oauth\signature\PlainText'
+		];
+		$oauthClient->setSignatureMethod($oauthSignatureMethod);
+		$returnedSignatureMethod = $oauthClient->getSignatureMethod();
+		$this->assertEquals($oauthSignatureMethod['class'], get_class($returnedSignatureMethod), 'Unable to setup signature method as config!');
+	}
+
+	/**
+	 * Data provider for [[testComposeUrl()]].
+	 * @return array test data.
+	 */
+	public function composeUrlDataProvider()
+	{
+		return [
+			[
+				'http://test.url',
+				[
+					'param1' => 'value1',
+					'param2' => 'value2',
+				],
+				'http://test.url?param1=value1&param2=value2',
+			],
+			[
+				'http://test.url?with=some',
+				[
+					'param1' => 'value1',
+					'param2' => 'value2',
+				],
+				'http://test.url?with=some&param1=value1&param2=value2',
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider composeUrlDataProvider
+	 *
+	 * @param string $url request URL.
+	 * @param array $params request params
+	 * @param string $expectedUrl expected composed URL.
+	 */
+	public function testComposeUrl($url, array $params, $expectedUrl)
+	{
+		$oauthClient = $this->createOAuthClient();
+		$composedUrl = $this->invokeOAuthClientMethod($oauthClient, 'composeUrl', [$url, $params]);
+		$this->assertEquals($expectedUrl, $composedUrl);
+	}
+
+	/**
+	 * Data provider for {@link testDetermineContentTypeByHeaders}.
+	 * @return array test data.
+	 */
+	public function determineContentTypeByHeadersDataProvider()
+	{
+		return [
+			[
+				['content_type' => 'application/json'],
+				'json'
+			],
+			[
+				['content_type' => 'application/x-www-form-urlencoded'],
+				'urlencoded'
+			],
+			[
+				['content_type' => 'application/xml'],
+				'xml'
+			],
+			[
+				['some_header' => 'some_header_value'],
+				'auto'
+			],
+			[
+				['content_type' => 'unknown'],
+				'auto'
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider determineContentTypeByHeadersDataProvider
+	 *
+	 * @param array $headers request headers.
+	 * @param string $expectedResponseType expected response type.
+	 */
+	public function testDetermineContentTypeByHeaders(array $headers, $expectedResponseType)
+	{
+		$oauthClient = $this->createOAuthClient();
+		$responseType = $this->invokeOAuthClientMethod($oauthClient, 'determineContentTypeByHeaders', [$headers]);
+		$this->assertEquals($expectedResponseType, $responseType);
+	}
+
+	/**
+	 * Data provider for [[testDetermineContentTypeByRaw]].
+	 * @return array test data.
+	 */
+	public function determineContentTypeByRawDataProvider()
+	{
+		return array(
+			['{name: value}', 'json'],
+			['name=value', 'urlencoded'],
+			['name1=value1&name2=value2', 'urlencoded'],
+			['<?xml version="1.0" encoding="UTF-8"?><tag>Value</tag>', 'xml'],
+			['<tag>Value</tag>', 'xml'],
+		);
+	}
+
+	/**
+	 * @dataProvider determineContentTypeByRawDataProvider
+	 *
+	 * @param string $rawResponse raw response content.
+	 * @param string $expectedResponseType expected response type.
+	 */
+	public function testDetermineContentTypeByRaw($rawResponse, $expectedResponseType)
+	{
+		$oauthClient = $this->createOAuthClient();
+		$responseType = $this->invokeOAuthClientMethod($oauthClient, 'determineContentTypeByRaw', [$rawResponse]);
+		$this->assertEquals($expectedResponseType, $responseType);
+	}
+
+	/**
+	 * Data provider for [[testApiUrl]].
+	 * @return array test data.
+	 */
+	public function apiUrlDataProvider()
+	{
+		return [
+			[
+				'http://api.base.url',
+				'sub/url',
+				'http://api.base.url/sub/url',
+			],
+			[
+				'http://api.base.url',
+				'http://api.base.url/sub/url',
+				'http://api.base.url/sub/url',
+			],
+			[
+				'http://api.base.url',
+				'https://api.base.url/sub/url',
+				'https://api.base.url/sub/url',
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider apiUrlDataProvider
+	 *
+	 * @param $apiBaseUrl
+	 * @param $apiSubUrl
+	 * @param $expectedApiFullUrl
+	 */
+	public function testApiUrl($apiBaseUrl, $apiSubUrl, $expectedApiFullUrl)
+	{
+		$oauthClient = $this->createOAuthClient();
+		$oauthClient->expects($this->any())->method('apiInternal')->will($this->returnArgument(1));
+
+		$accessToken = new Token();
+		$accessToken->setToken('test_access_token');
+		$accessToken->setExpireDuration(1000);
+		$oauthClient->setAccessToken($accessToken);
+
+		$oauthClient->apiBaseUrl = $apiBaseUrl;
+
+		$this->assertEquals($expectedApiFullUrl, $oauthClient->api($apiSubUrl));
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/Client1Test.php b/tests/unit/extensions/authclient/oauth/Client1Test.php
new file mode 100644
index 0000000..e882a68
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/Client1Test.php
@@ -0,0 +1,109 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth;
+
+use yii\authclient\oauth\Client1;
+use yii\authclient\oauth\signature\PlainText;
+use yii\authclient\oauth\Token;
+use yiiunit\extensions\authclient\TestCase;
+
+class Client1Test extends TestCase
+{
+	protected function setUp()
+	{
+		$this->mockApplication([], '\yii\web\Application');
+	}
+
+	/**
+	 * Invokes the OAuth client method even if it is protected.
+	 * @param Client1 $oauthClient OAuth client instance.
+	 * @param string $methodName name of the method to be invoked.
+	 * @param array $arguments method arguments.
+	 * @return mixed method invoke result.
+	 */
+	protected function invokeOAuthClientMethod($oauthClient, $methodName, array $arguments = [])
+	{
+		$classReflection = new \ReflectionClass(get_class($oauthClient));
+		$methodReflection = $classReflection->getMethod($methodName);
+		$methodReflection->setAccessible(true);
+		$result = $methodReflection->invokeArgs($oauthClient, $arguments);
+		$methodReflection->setAccessible(false);
+		return $result;
+	}
+
+	// Tests :
+
+	public function testSignRequest()
+	{
+		$oauthClient = new Client1();
+
+		$oauthSignatureMethod = new PlainText();
+		$oauthClient->setSignatureMethod($oauthSignatureMethod);
+
+		$signedParams = $this->invokeOAuthClientMethod($oauthClient, 'signRequest', ['GET', 'http://test.url', []]);
+		$this->assertNotEmpty($signedParams['oauth_signature'], 'Unable to sign request!');
+	}
+
+	/**
+	 * Data provider for [[testComposeAuthorizationHeader()]].
+	 * @return array test data.
+	 */
+	public function composeAuthorizationHeaderDataProvider()
+	{
+		return [
+			[
+				'',
+				[
+					'oauth_test_name_1' => 'oauth_test_value_1',
+					'oauth_test_name_2' => 'oauth_test_value_2',
+				],
+				'Authorization: OAuth oauth_test_name_1="oauth_test_value_1", oauth_test_name_2="oauth_test_value_2"'
+			],
+			[
+				'test_realm',
+				[
+					'oauth_test_name_1' => 'oauth_test_value_1',
+					'oauth_test_name_2' => 'oauth_test_value_2',
+				],
+				'Authorization: OAuth realm="test_realm", oauth_test_name_1="oauth_test_value_1", oauth_test_name_2="oauth_test_value_2"'
+			],
+			[
+				'',
+				[
+					'oauth_test_name_1' => 'oauth_test_value_1',
+					'test_name_2' => 'test_value_2',
+				],
+				'Authorization: OAuth oauth_test_name_1="oauth_test_value_1"'
+			],
+		];
+	}
+
+	/**
+	 * @dataProvider composeAuthorizationHeaderDataProvider
+	 *
+	 * @param string $realm authorization realm.
+	 * @param array $params request params.
+	 * @param string $expectedAuthorizationHeader expected authorization header.
+	 */
+	public function testComposeAuthorizationHeader($realm, array $params, $expectedAuthorizationHeader)
+	{
+		$oauthClient = new Client1();
+		$authorizationHeader = $this->invokeOAuthClientMethod($oauthClient, 'composeAuthorizationHeader', [$params, $realm]);
+		$this->assertEquals($expectedAuthorizationHeader, $authorizationHeader);
+	}
+
+	public function testBuildAuthUrl() {
+		$oauthClient = new Client1();
+		$authUrl = 'http://test.auth.url';
+		$oauthClient->authUrl = $authUrl;
+
+		$requestTokenToken = 'test_request_token';
+		$requestToken = new Token();
+		$requestToken->setToken($requestTokenToken);
+
+		$builtAuthUrl = $oauthClient->buildAuthUrl($requestToken);
+
+		$this->assertContains($authUrl, $builtAuthUrl, 'No auth URL present!');
+		$this->assertContains($requestTokenToken, $builtAuthUrl, 'No token present!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/Client2Test.php b/tests/unit/extensions/authclient/oauth/Client2Test.php
new file mode 100644
index 0000000..c8eeab8
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/Client2Test.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth;
+
+use yii\authclient\oauth\Client2;
+use yiiunit\extensions\authclient\TestCase;
+
+class Client2Test extends TestCase
+{
+	protected function setUp()
+	{
+		$this->mockApplication([], '\yii\web\Application');
+	}
+
+	// Tests :
+
+	public function testBuildAuthUrl()
+	{
+		$oauthClient = new Client2();
+		$authUrl = 'http://test.auth.url';
+		$oauthClient->authUrl = $authUrl;
+		$clientId = 'test_client_id';
+		$oauthClient->clientId = $clientId;
+		$returnUrl = 'http://test.return.url';
+		$oauthClient->setReturnUrl($returnUrl);
+
+		$builtAuthUrl = $oauthClient->buildAuthUrl();
+
+		$this->assertContains($authUrl, $builtAuthUrl, 'No auth URL present!');
+		$this->assertContains($clientId, $builtAuthUrl, 'No client id present!');
+		$this->assertContains(rawurlencode($returnUrl), $builtAuthUrl, 'No return URL present!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/TokenTest.php b/tests/unit/extensions/authclient/oauth/TokenTest.php
new file mode 100644
index 0000000..d319198
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/TokenTest.php
@@ -0,0 +1,133 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth;
+
+use yii\authclient\oauth\Token;
+use yiiunit\extensions\authclient\TestCase;
+
+class TokenTest extends TestCase
+{
+	public function testCreate()
+	{
+		$config = [
+			'tokenParamKey' => 'test_token_param_key',
+			'tokenSecretParamKey' => 'test_token_secret_param_key',
+		];
+		$oauthToken = new Token($config);
+		$this->assertTrue(is_object($oauthToken), 'Unable to create access token!');
+		foreach ($config as $name => $value) {
+			$this->assertEquals($value, $oauthToken->$name, 'Unable to setup attributes by constructor!');
+		}
+		$this->assertTrue($oauthToken->createTimestamp > 0, 'Unable to fill create timestamp!');
+	}
+
+	public function testSetupParams()
+	{
+		$oauthToken = new Token();
+
+		$params = [
+			'name_1' => 'value_1',
+			'name_2' => 'value_2',
+		];
+		$oauthToken->setParams($params);
+		$this->assertEquals($params, $oauthToken->getParams(), 'Unable to setup params!');
+
+		$newParamName = 'new_param_name';
+		$newParamValue = 'new_param_value';
+		$oauthToken->setParam($newParamName, $newParamValue);
+		$this->assertEquals($newParamValue, $oauthToken->getParam($newParamName), 'Unable to setup param by name!');
+	}
+
+	/**
+	 * @depends testSetupParams
+	 */
+	public function testSetupParamsShortcuts()
+	{
+		$oauthToken = new Token();
+
+		$token = 'test_token_value';
+		$oauthToken->setToken($token);
+		$this->assertEquals($token, $oauthToken->getToken(), 'Unable to setup token!');
+
+		$tokenSecret = 'test_token_secret';
+		$oauthToken->setTokenSecret($tokenSecret);
+		$this->assertEquals($tokenSecret, $oauthToken->getTokenSecret(), 'Unable to setup token secret!');
+
+		$tokenExpireDuration = rand(1000, 2000);
+		$oauthToken->setExpireDuration($tokenExpireDuration);
+		$this->assertEquals($tokenExpireDuration, $oauthToken->getExpireDuration(), 'Unable to setup expire duration!');
+	}
+
+	/**
+	 * Data provider for {@link testAutoFetchExpireDuration}.
+	 * @return array test data.
+	 */
+	public function autoFetchExpireDurationDataProvider()
+	{
+		return [
+			[
+				['expire_in' => 123345],
+				123345
+			],
+			[
+				['expire' => 233456],
+				233456
+			],
+			[
+				['expiry_in' => 34567],
+				34567
+			],
+			[
+				['expiry' => 45678],
+				45678
+			],
+		];
+	}
+
+	/**
+	 * @depends testSetupParamsShortcuts
+	 * @dataProvider autoFetchExpireDurationDataProvider
+	 *
+	 * @param array $params
+	 * @param $expectedExpireDuration
+	 */
+	public function testAutoFetchExpireDuration(array $params, $expectedExpireDuration)
+	{
+		$oauthToken = new Token();
+		$oauthToken->setParams($params);
+		$this->assertEquals($expectedExpireDuration, $oauthToken->getExpireDuration());
+	}
+
+	/**
+	 * @depends testSetupParamsShortcuts
+	 */
+	public function testGetIsExpired()
+	{
+		$oauthToken = new Token();
+		$expireDuration = 3600;
+		$oauthToken->setExpireDuration($expireDuration);
+
+		$this->assertFalse($oauthToken->getIsExpired(), 'Not expired token check fails!');
+
+		$oauthToken->createTimestamp = $oauthToken->createTimestamp - ($expireDuration +1);
+		$this->assertTrue($oauthToken->getIsExpired(), 'Expired token check fails!');
+	}
+
+	/**
+	 * @depends testGetIsExpired
+	 */
+	public function testGetIsValid()
+	{
+		$oauthToken = new Token();
+		$expireDuration = 3600;
+		$oauthToken->setExpireDuration($expireDuration);
+
+		$this->assertFalse($oauthToken->getIsValid(), 'Empty token is valid!');
+
+		$oauthToken->setToken('test_token');
+		$this->assertTrue($oauthToken->getIsValid(), 'Filled up token is invalid!');
+
+		$oauthToken->createTimestamp = $oauthToken->createTimestamp - ($expireDuration +1);
+		$this->assertFalse($oauthToken->getIsValid(), 'Expired token is valid!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/signature/BaseMethodTest.php b/tests/unit/extensions/authclient/oauth/signature/BaseMethodTest.php
new file mode 100644
index 0000000..e6f5b33
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/signature/BaseMethodTest.php
@@ -0,0 +1,50 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth\signature;
+
+use yiiunit\extensions\authclient\TestCase;
+
+class BaseMethodTest extends TestCase
+{
+	/**
+	 * Creates test signature method instance.
+	 * @return \yii\authclient\oauth\signature\BaseMethod
+	 */
+	protected function createTestSignatureMethod()
+	{
+		$signatureMethod = $this->getMock('\yii\authclient\oauth\signature\BaseMethod', ['getName', 'generateSignature']);
+		$signatureMethod->expects($this->any())->method('getName')->will($this->returnValue('testMethodName'));
+		$signatureMethod->expects($this->any())->method('generateSignature')->will($this->returnValue('testSignature'));
+		return $signatureMethod;
+	}
+
+	// Tests :
+
+	public function testGenerateSignature()
+	{
+		$signatureMethod = $this->createTestSignatureMethod();
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+
+		$signature = $signatureMethod->generateSignature($baseString, $key);
+
+		$this->assertNotEmpty($signature, 'Unable to generate signature!');
+	}
+
+	/**
+	 * @depends testGenerateSignature
+	 */
+	public function testVerify()
+	{
+		$signatureMethod = $this->createTestSignatureMethod();
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+		$signature = 'unsigned';
+		$this->assertFalse($signatureMethod->verify($signature, $baseString, $key), 'Unsigned signature is valid!');
+
+		$generatedSignature = $signatureMethod->generateSignature($baseString, $key);
+		$this->assertTrue($signatureMethod->verify($generatedSignature, $baseString, $key), 'Generated signature is invalid!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/signature/HmacSha1Test.php b/tests/unit/extensions/authclient/oauth/signature/HmacSha1Test.php
new file mode 100644
index 0000000..409c885
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/signature/HmacSha1Test.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth\signature;
+
+use yii\authclient\oauth\signature\HmacSha1;
+use yiiunit\extensions\authclient\TestCase;
+
+class HmacSha1Test extends TestCase
+{
+	public function testGenerateSignature()
+	{
+		$signatureMethod = new HmacSha1();
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+
+		$signature = $signatureMethod->generateSignature($baseString, $key);
+		$this->assertNotEmpty($signature, 'Unable to generate signature!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/signature/PlainTextTest.php b/tests/unit/extensions/authclient/oauth/signature/PlainTextTest.php
new file mode 100644
index 0000000..25f9abc
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/signature/PlainTextTest.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth\signature;
+
+use yii\authclient\oauth\signature\PlainText;
+use yiiunit\extensions\authclient\TestCase;
+
+class PlainTextTest extends TestCase
+{
+	public function testGenerateSignature()
+	{
+		$signatureMethod = new PlainText();
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+
+		$signature = $signatureMethod->generateSignature($baseString, $key);
+		$this->assertNotEmpty($signature, 'Unable to generate signature!');
+	}
+}
\ No newline at end of file
diff --git a/tests/unit/extensions/authclient/oauth/signature/RsaSha1Test.php b/tests/unit/extensions/authclient/oauth/signature/RsaSha1Test.php
new file mode 100644
index 0000000..e4a69dc
--- /dev/null
+++ b/tests/unit/extensions/authclient/oauth/signature/RsaSha1Test.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace yiiunit\extensions\authclient\oauth\signature;
+
+use yii\authclient\oauth\signature\RsaSha1;
+use yiiunit\extensions\authclient\TestCase;
+
+class RsaSha1Test extends TestCase
+{
+	/**
+	 * Returns test public certificate string.
+	 * @return string public certificate string.
+	 */
+	protected function getTestPublicCertificate()
+	{
+		return '-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----';
+	}
+
+	/**
+	 * Returns test private certificate string.
+	 * @return string private certificate string.
+	 */
+	protected function getTestPrivateCertificate()
+	{
+		return '-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----';
+	}
+
+	// Tests :
+
+	public function testGenerateSignature()
+	{
+		$signatureMethod = new RsaSha1();
+		$signatureMethod->setPrivateCertificate($this->getTestPrivateCertificate());
+		$signatureMethod->setPublicCertificate($this->getTestPublicCertificate());
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+
+		$signature = $signatureMethod->generateSignature($baseString, $key);
+		$this->assertNotEmpty($signature, 'Unable to generate signature!');
+	}
+
+	/**
+	 * @depends testGenerateSignature
+	 */
+	public function testVerify()
+	{
+		$signatureMethod = new RsaSha1();
+		$signatureMethod->setPrivateCertificate($this->getTestPrivateCertificate());
+		$signatureMethod->setPublicCertificate($this->getTestPublicCertificate());
+
+		$baseString = 'test_base_string';
+		$key = 'test_key';
+		$signature = 'unsigned';
+		$this->assertFalse($signatureMethod->verify($signature, $baseString, $key), 'Unsigned signature is valid!');
+
+		$generatedSignature = $signatureMethod->generateSignature($baseString, $key);
+		$this->assertTrue($signatureMethod->verify($generatedSignature, $baseString, $key), 'Generated signature is invalid!');
+	}
+
+	public function testInitPrivateCertificate()
+	{
+		$signatureMethod = new RsaSha1();
+
+		$certificateFileName = __FILE__;
+		$signatureMethod->privateCertificateFile = $certificateFileName;
+		$this->assertEquals(file_get_contents($certificateFileName), $signatureMethod->getPrivateCertificate(), 'Unable to fetch private certificate from file!');
+	}
+
+	public function testInitPublicCertificate()
+	{
+		$signatureMethod = new RsaSha1();
+
+		$certificateFileName = __FILE__;
+		$signatureMethod->publicCertificateFile = $certificateFileName;
+		$this->assertEquals(file_get_contents($certificateFileName), $signatureMethod->getPublicCertificate(), 'Unable to fetch public certificate from file!');
+	}
+}
\ No newline at end of file