diff --git a/CMakeLists.txt b/CMakeLists.txt
index 205405f..b57bdcf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,7 +13,7 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #
 
 cmake_minimum_required(VERSION 3.12)
diff --git a/main.cc b/main.cc
index b70fd8a..d9fc9f3 100644
--- a/main.cc
+++ b/main.cc
@@ -13,7 +13,7 @@
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
- *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 int main(void) {