diff --git a/gap-matgrp.spec b/gap-matgrp.spec
index ec894b9..f4e2d3f 100644
--- a/gap-matgrp.spec
+++ b/gap-matgrp.spec
@@ -24,7 +24,7 @@ License:        GPL-2.0 or GPL-3.0
 Group:          Productivity/Scientific/Math
 URL:            http://www.math.colostate.edu/~hulpke
 
-Source:         http://www.gap-system.org/pub/gap/gap4/tar.bz2/packages/matgrp04.tar.bz2
+Source:         https://www.gap-system.org/pub/gap/gap4/tar.bz2/packages/matgrp04.tar.bz2
 BuildArch:      noarch
 BuildRoot:      %{_tmppath}/%{name}-%{version}-build
 BuildRequires:  gap-rpm-devel