diff --git a/requirements_dev.txt b/requirements_dev.txt
index 0378f87..238598b 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -6,7 +6,7 @@ flake8==3.4.1
 tox==2.9.1
 coverage==4.4.1
 Sphinx==1.6.4
-cryptography==2.4.2
+cryptography==3.2.1
 PyYAML==5.3.1
 pytest==3.2.3
 pytest-runner==2.12.1