diff --git a/usr.bin/caesar/caesar.c b/usr.bin/caesar/caesar.c
index 011f9c8e063..0717f263764 100644
--- a/usr.bin/caesar/caesar.c
+++ b/usr.bin/caesar/caesar.c
@@ -1,4 +1,6 @@
 /*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1989, 1993
  *	The Regents of the University of California.  All rights reserved.
  *