diff --git a/src/Fetch/Message.php b/src/Fetch/Message.php
index 3644c91..cab27f8 100644
--- a/src/Fetch/Message.php
+++ b/src/Fetch/Message.php
@@ -481,16 +481,17 @@ class Message
      */
     public static function decode($data, $encoding)
     {
-        if (!is_numeric($encoding))
+        if (!is_numeric($encoding)) {
             $encoding = strtolower($encoding);
+        }
 
-        switch ($encoding) {
-            case 'quoted-printable':
-            case 4:
+        switch (true) {
+            case $encoding === 'quoted-printable':
+            case $encoding === 4:
                 return quoted_printable_decode($data);
 
-            case 'base64':
-            case 3:
+            case $encoding === 'base64':
+            case $encoding === 3:
                 return base64_decode($data);
 
             default: