diff --git a/requirements.txt b/requirements.txt
index 9c32052d0..05248d8b0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -20,3 +20,4 @@ requests>=2.0.0
 stomp.py>=4.1.17
 texttable>=0.8.8
 twilio==6.0.0
+cryptography<3.4
diff --git a/setup.py b/setup.py
index 2845836a7..56f053c2c 100644
--- a/setup.py
+++ b/setup.py
@@ -47,6 +47,7 @@
         'stomp.py>=4.1.17',
         'texttable>=0.8.8',
         'twilio>=6.0.0,<6.1',
-        'cffi>=1.11.5'
+        'cffi>=1.11.5',
+        'cryptography<3.4'
     ]
 )