diff --git a/requirements_dev.txt b/requirements_dev.txt
index 47c972e..1f1a190 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,6 +6,6 @@ flake8==2.6.0
 tox==2.3.1
 coverage==4.1
 Sphinx==1.4.8
-cryptography==1.7
+cryptography==3.3.1
 PyYAML==3.11
 pytest==2.9.2