diff --git a/requirements_dev.txt b/requirements_dev.txt
index e77cc05..23215f4 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ flake8==3.3.0
 tox==2.7.0
 coverage==4.4
 Sphinx==1.6.1
-cryptography==1.8.2
+cryptography==1.9
 PyYAML==3.12
 pytest==3.1.3
 funcparserlib==0.3.6