diff --git a/pyproject.toml b/pyproject.toml
index 502a22d9..1cb1d916 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,6 +22,7 @@ bcrypt = "~3"
 blinker = "~1.4"
 bleach = "~3.1"
 celery = {version = "~4.3",extras = ["redis"]}
+cryptography = "2.7"
 commonmark = "~0.9"
 
 # These must match the version of ElasticSearch used: