diff --git a/requirements_dev.txt b/requirements_dev.txt
index eb0e7db..1e97192 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,7 +3,7 @@ pip==9.0.1
 # release management
 bumpversion==0.5.3
 wheel==0.29.0
-cryptography==1.9
+cryptography==3.3.1
 
 # test, lint, coverage
 flake8==3.3.0