diff --git a/ctaocrypt/src/poly1305.c b/ctaocrypt/src/poly1305.c
index c246394f9..718d2fb7c 100644
--- a/ctaocrypt/src/poly1305.c
+++ b/ctaocrypt/src/poly1305.c
@@ -17,6 +17,8 @@
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ *
+ * Based off the implementation by Andrew Moon
  */
 
 #ifdef HAVE_POLY1305