diff --git a/sources/requirements-ynh.txt b/sources/requirements-ynh.txt
index 602a959..4d3a13d 100644
--- a/sources/requirements-ynh.txt
+++ b/sources/requirements-ynh.txt
@@ -11,3 +11,4 @@ pyopenssl==0.15.1
 python-dateutil==2.4.2
 pyyaml==3.11
 requests==2.9.1
+cffi>=1.6
\ No newline at end of file