diff --git a/NG-RO/debian/python3-osm-ng-ro.postinst b/NG-RO/debian/python3-osm-ng-ro.postinst
index 09b59d2..87416ac 100755
--- a/NG-RO/debian/python3-osm-ng-ro.postinst
+++ b/NG-RO/debian/python3-osm-ng-ro.postinst
@@ -21,5 +21,4 @@
 echo "Installing python dependencies via pip..."
 
 # python3 -m pip install -U pip
-python3 -m pip install cherrypy==18.1.2
-
+python3 -m pip install -U "cherrypy==18.1.2"  "cryptography>=2.5"
diff --git a/NG-RO/setup.py b/NG-RO/setup.py
index a001836..a6cf47a 100644
--- a/NG-RO/setup.py
+++ b/NG-RO/setup.py
@@ -40,7 +40,7 @@
         'jsonschema',
         'PyYAML',
         'requests',
-        'cryptography',
+        'cryptography',  # >=2.5  installed right version with the debian post-install script
         'osm-im @ git+https://osm.etsi.org/gerrit/osm/IM.git#egg=osm-im',
         "osm-ro-plugin @ git+https://osm.etsi.org/gerrit/osm/RO.git#egg=osm-ro-plugin&subdirectory=RO-plugin",
     ],