diff --git a/lib/private/SystemConfig.php b/lib/private/SystemConfig.php
index 5818f78f96267..d3fd1f2ab049c 100644
--- a/lib/private/SystemConfig.php
+++ b/lib/private/SystemConfig.php
@@ -73,6 +73,7 @@ class SystemConfig {
 				// S3
 				'key' => true,
 				'secret' => true,
+				'sse_c_key' => true,
 				// Swift v2
 				'username' => true,
 				'password' => true,