diff --git a/src/libstrongswan/credentials/certificates/x509.h b/src/libstrongswan/credentials/certificates/x509.h
index 9d4054710..3a90db53c 100644
--- a/src/libstrongswan/credentials/certificates/x509.h
+++ b/src/libstrongswan/credentials/certificates/x509.h
@@ -11,6 +11,8 @@
  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * for more details.
+ *
+ * $Id$
  */
 
 /**