diff --git a/src/index.php b/src/index.php
index 07fd6c1..5a151b8 100644
--- a/src/index.php
+++ b/src/index.php
@@ -39,47 +39,6 @@ function error($status, $text) {
 
 
 
-
-
-
-
-
-/**
- * Remove illegal characters from address.
- * @param $address
- * @return string clean address
- */
-function _clean_address($address) {
-    return strtolower(filter_var($address, FILTER_SANITIZE_EMAIL));
-}
-
-
-/**
- * Remove illegal characters from username and remove everything after the @-sign. You may extend it if your server supports them.
- * @param $address
- * @return string clean username
- */
-function _clean_username($address) {
-    global $config;
-    $username = strtolower($address);
-    $username = preg_replace('/@.*$/', "", $username);   // remove part after @
-    $username = preg_replace('/[^A-Za-z0-9_.+-]/', "", $username);   // remove special characters
-
-    if (in_array($username, $config['blocked_usernames'])) {
-        // Forbidden name!
-        return '';
-    }
-
-    return $username;
-}
-
-
-function _clean_domain($address) {
-    $username = strtolower($address);
-    $username = preg_replace('/^.*@/', "", $username);   // remove part before @
-    return preg_replace('/[^A-Za-z0-9_.+-]/', "", $username);   // remove special characters
-}
-
 function redirect_to_random(array $domains) {
     $wordLength = rand(3, 8);
     $container = new PronounceableWord_DependencyInjectionContainer();
diff --git a/src/user.php b/src/user.php
index 2791c55..6e02745 100644
--- a/src/user.php
+++ b/src/user.php
@@ -17,19 +17,56 @@ class User {
     }
 
     public static function parseDomain(string $address): User {
-        $clean_address = _clean_address($address);
+        $clean_address = User::_clean_address($address);
         $user = new User();
-        $user->username = _clean_username($clean_address);
-        $user->domain = _clean_domain($clean_address);
+        $user->username = User::_clean_username($clean_address);
+        $user->domain = User::_clean_domain($clean_address);
         $user->address = $user->username . '@' . $user->domain;
         return $user;
     }
 
     public static function parseUsernameAndDomain(string $username, string $domain): User {
         $user = new User();
-        $user->username = _clean_username($username);
-        $user->domain = _clean_domain($domain);
+        $user->username = User::_clean_username($username);
+        $user->domain = User::_clean_domain($domain);
         $user->address = $user->username . '@' . $user->domain;
         return $user;
     }
+
+    /**
+     * Remove illegal characters from address.
+     * @param $address
+     * @return string clean address
+     */
+    private static function _clean_address($address) {
+        return strtolower(filter_var($address, FILTER_SANITIZE_EMAIL));
+    }
+
+
+    /**
+     * Remove illegal characters from username and remove everything after the @-sign. You may extend it if your server supports them.
+     * @param $address
+     * @return string clean username
+     */
+    private static function _clean_username($address) {
+        global $config;
+        $username = strtolower($address);
+        $username = preg_replace('/@.*$/', "", $username);   // remove part after @
+        $username = preg_replace('/[^A-Za-z0-9_.+-]/', "", $username);   // remove special characters
+
+        if (in_array($username, $config['blocked_usernames'])) {
+            // Forbidden name!
+            return '';
+        }
+
+        return $username;
+    }
+
+
+    private static function _clean_domain($address) {
+        $username = strtolower($address);
+        $username = preg_replace('/^.*@/', "", $username);   // remove part before @
+        return preg_replace('/[^A-Za-z0-9_.+-]/', "", $username);   // remove special characters
+    }
+
 }