diff --git a/cloud/shepherd/manager/ssh_key_signer.go b/cloud/shepherd/manager/ssh_key_signer.go
index 7a8d08a..b28b0b5 100644
--- a/cloud/shepherd/manager/ssh_key_signer.go
+++ b/cloud/shepherd/manager/ssh_key_signer.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package manager
 
 import (