diff --git a/src/Connection.php b/src/Connection.php
index 98365f8..401e0db 100644
--- a/src/Connection.php
+++ b/src/Connection.php
@@ -61,6 +61,10 @@ public function __construct(Array $options, LoopInterface $loop = null, Connecto
         if (isset($options['authid'])) {
             $this->client->setAuthId($options['authid']);
         }
+        //Set Authextra
+        if (isset($options['authextra'])) {
+            $this->client->setAuthextra($options['authextra']);
+        }
 
         //Register Handlers
         $this->handleOnChallenge();
@@ -167,8 +171,12 @@ private function handleOnChallenge()
             $this->client->setAuthMethods($options['authmethods']);
 
             $this->client->on('challenge', function (ClientSession $session, ChallengeMessage $msg) use ($options) {
+                $extra = null;
                 $token = call_user_func($options['onChallenge'], $session, $msg->getAuthMethod(), $msg);
-                $session->sendMessage(new AuthenticateMessage($token));
+                if (is_array($token) && count($token) >= 2) {
+                    [$token, $extra] = $token;
+                }
+                $session->sendMessage(new AuthenticateMessage($token, $extra));
             });
         }
     }
diff --git a/src/Peer/Client.php b/src/Peer/Client.php
index 38c20fe..86537d9 100644
--- a/src/Peer/Client.php
+++ b/src/Peer/Client.php
@@ -124,6 +124,11 @@ class Client implements EventEmitterInterface, ClientInterface
      */
     private $attemptRetry = true;
 
+    /**
+     * @var \stdClass|null
+     */
+    private $authextra;
+
 
     /**
      * Constructor
@@ -143,6 +148,7 @@ public function __construct($realm, LoopInterface $loop = null)
         $this->session              = null;
         $this->clientAuthenticators = [];
         $this->authId               = 'anonymous';
+        $this->authextra            = null;
 
         $this->reconnectOptions = [
             'max_retries'         => 15,
@@ -271,6 +277,9 @@ public function startSession(ClientSession $session)
 
         $details->authmethods = $this->authMethods;
         $details->authid      = $this->authId;
+        if ($this->authextra !== null) {
+            $details->authextra = $this->authextra;
+        }
 
         $session->setRealm($this->realm);
 
@@ -608,6 +617,22 @@ public function setAuthMethods($authMethods)
         $this->authMethods = $authMethods;
     }
 
+    /**
+     * @return \stdClass|null
+     */
+    public function getAuthextra()
+    {
+        return $this->authextra;
+    }
+
+    /**
+     * @param \stdClass|null $authextra
+     */
+    public function setAuthextra($authextra)
+    {
+        $this->authextra = $authextra === null ? null : (object)$authextra;
+    }
+
     /**
      * Get client session
      *