diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 71dcfdc6d14..ad2cdd34203 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -6804,17 +6804,12 @@ class emoticon_manager {
  *
  * @todo Finish documenting this function
  *
- * @param string $data        Data to encrypt.
- * @param bool $usesecurekey  Lets us know if we are using the old or new password.
- * @return string             The now encrypted data.
+ * @param string $data Data to encrypt
+ * @return string The now encrypted data
  */
-function rc4encrypt($data, $usesecurekey = false) {
-    if (!$usesecurekey) {
-        $passwordkey = 'nfgjeingjk';
-    } else {
-        $passwordkey = get_site_identifier();
-    }
-    return endecrypt($passwordkey, $data, '');
+function rc4encrypt($data) {
+    $password = get_site_identifier();
+    return endecrypt($password, $data, '');
 }
 
 /**
@@ -6822,17 +6817,12 @@ function rc4encrypt($data, $usesecurekey = false) {
  *
  * @todo Finish documenting this function
  *
- * @param string $data        Data to decrypt.
- * @param bool $usesecurekey  Lets us know if we are using the old or new password.
- * @return string             The now decrypted data.
+ * @param string $data Data to decrypt
+ * @return string The now decrypted data
  */
-function rc4decrypt($data, $usesecurekey = false) {
-    if (!$usesecurekey) {
-        $passwordkey = 'nfgjeingjk';
-    } else {
-        $passwordkey = get_site_identifier();
-    }
-    return endecrypt($passwordkey, $data, 'de');
+function rc4decrypt($data) {
+    $password = get_site_identifier();
+    return endecrypt($password, $data, 'de');
 }
 
 /**
diff --git a/lib/sessionlib.php b/lib/sessionlib.php
index ad20c4dac76..73cbf2a1fb6 100644
--- a/lib/sessionlib.php
+++ b/lib/sessionlib.php
@@ -828,7 +828,7 @@ function set_moodle_cookie($username) {
 
     if ($username !== '') {
         // set username cookie for 60 days
-        setcookie($cookiename, rc4encrypt($username, true), time()+(DAYSECS*60), $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $CFG->cookiesecure, $CFG->cookiehttponly);
+        setcookie($cookiename, rc4encrypt($username), time()+(DAYSECS*60), $CFG->sessioncookiepath, $CFG->sessioncookiedomain, $CFG->cookiesecure, $CFG->cookiehttponly);
     }
 }
 
@@ -849,18 +849,10 @@ function get_moodle_cookie() {
     if (empty($_COOKIE[$cookiename])) {
         return '';
     } else {
-        $username = rc4decrypt($_COOKIE[$cookiename], true);
-        if ($username != clean_param($username, PARAM_USERNAME)) {
-            $username = rc4decrypt($_COOKIE[$cookiename]);
-            if ($username == clean_param($username, PARAM_USERNAME)) {
-                set_moodle_cookie($username);
-            } else {
-                $username = '';
-            }
-        }
+        $username = rc4decrypt($_COOKIE[$cookiename]);
         if ($username === 'guest' or $username === 'nobody') {
             // backwards compatibility - we do not set these cookies any more
-            $username = '';
+            return '';
         }
         return $username;
     }