diff --git a/sources.list.d/ftp.uni-stuttgart.de-rus.sources b/sources.list.d/ftp.uni-stuttgart.de-rus.sources
index 33ff525..33e77f0 100644
--- a/sources.list.d/ftp.uni-stuttgart.de-rus.sources
+++ b/sources.list.d/ftp.uni-stuttgart.de-rus.sources
@@ -1,5 +1,5 @@
 Types: deb deb-src
-URIs: http://ftp.uni-stuttgart.de/rus/
+URIs: https://ftp.uni-stuttgart.de/rus/
 Suites: generic
 Components: main
 Signed-By: /etc/apt/single-keys/ftp.uni-stuttgart.de-rus.gpg