diff --git a/requirements.txt b/requirements.txt
index b9bda38d..ad7731e8 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,6 +24,7 @@ uwsgi==2.0.17
 jsonpath-ng==1.4.3
 jsonschema==2.6.0
 beaker==1.9.1
+cryptography>=2.1 # BSD/Apache-2.0
 
 oslo.cache>=1.30.1 # Apache-2.0
 oslo.concurrency>=3.27.0 # Apache-2.0