diff --git a/requirements_dev.txt b/requirements_dev.txt
index 0524204..cb525c7 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -7,7 +7,7 @@ tox==2.3.1
 coverage==4.1
 Sphinx==1.4.8
 mypy==0.470; python_version >= '3.2'
-cryptography==1.7
+cryptography==3.2
 PyYAML==3.11
 pytest==2.9.2
 autopep8==1.2.4