diff --git a/lib/SimpleSAML/Utils/HTTP.php b/lib/SimpleSAML/Utils/HTTP.php
index 1acdea6726ac4508eb71a2b4c2a2bb108f7b8db7..d49b553b1ae92df0d2445d44a8c1eadc7b471d27 100644
--- a/lib/SimpleSAML/Utils/HTTP.php
+++ b/lib/SimpleSAML/Utils/HTTP.php
@@ -85,8 +85,8 @@ class HTTP
             return false;
         }
 
-        // otherwise, HTTPS will be a non-empty string
-        return $_SERVER['HTTPS'] !== '';
+        // otherwise, HTTPS will be non-empty
+        return !empty($_SERVER['HTTPS']);
     }