diff --git a/requirements_dev.txt b/requirements_dev.txt
index 7189118..e9f1ef0 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ flake8==3.8.4
 tox==3.20.1
 coverage==5.3
 Sphinx==3.2.1
-cryptography==2.8
+cryptography==3.3.1
 PyYAML==5.3.1
 pytest==5.3.5
 pytest-runner==5.2