diff --git a/conf/app.src b/conf/app.src
index ed3d93d..91dbea3 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -1,6 +1,6 @@
 SOURCE_URL=https://github.com/duniter/cesium/releases/download/v1.3.11/cesium-v1.3.11-web.zip
 SOURCE_SUM=
-SOURCE_SUM_PRG=
+SOURCE_SUM_PRG=sha256sum
 SOURCE_FORMAT=zip
 SOURCE_IN_SUBDIR=false
 SOURCE_FILENAME=