diff --git a/app/library/Auth.php b/app/library/Auth.php
index 33730ab..ade7a70 100644
--- a/app/library/Auth.php
+++ b/app/library/Auth.php
@@ -9,10 +9,7 @@ use App\Model\Data\User,
 
 class Auth extends Component
 {
-    /**
-     * @var string
-     */
-    protected $_session_key = 'auth';
+    const SESSION_KEY = 'auth';
 
     /**
      * Login using email/user + password combination.
@@ -92,7 +89,7 @@ class Auth extends Component
      */
     public function setIdentity($identity)
     {
-        $this->session->set($this->_session_key, $identity);
+        $this->session->set(self::SESSION_KEY, $identity);
         return $this;
     }
 
@@ -101,7 +98,7 @@ class Auth extends Component
      */
     public function getIdentity()
     {
-        $id = $this->session->get($this->_session_key);
+        $id = $this->session->get(self::SESSION_KEY);
 
         if ($id !== null) {
             return User::findFirst($id);
@@ -116,7 +113,7 @@ class Auth extends Component
     {
         if ($this->hasIdentity()) {
 
-            $id = $this->session->get($this->_session_key);
+            $id = $this->session->get(self::SESSION_KEY);
 
             return User::findFirst($id);
         }
@@ -128,8 +125,6 @@ class Auth extends Component
         return $this->getIdentity() !== NULL;
     }
 
-
-
     /**
      * Clears the identity information.
      *
@@ -137,7 +132,7 @@ class Auth extends Component
      */
     public function clearIdentity()
     {
-        $this->session->remove($this->_session_key);
+        $this->session->remove(self::SESSION_KEY);
         return $this;
     }
 }