diff --git a/pkgs/development/python-modules/rsa/default.nix b/pkgs/development/python-modules/rsa/default.nix
index 82eedf70cb09..c062aad4c4be 100644
--- a/pkgs/development/python-modules/rsa/default.nix
+++ b/pkgs/development/python-modules/rsa/default.nix
@@ -3,18 +3,19 @@
 , fetchPypi
 , unittest2
 , pyasn1
+, mock
 }:
 
 buildPythonPackage rec {
   pname = "rsa";
-  version = "3.4.2";
+  version = "4.0";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "1dcxvszbikgzh99ybdc7jq0zb9wspy2ds8z9mjsqiyv3q884xpr5";
+    sha256 = "1a836406405730121ae9823e19c6e806c62bbad73f890574fff50efa4122c487";
   };
 
-  nativeBuildInputs = [ unittest2 ];
+  checkInputs = [ unittest2 mock ];
   propagatedBuildInputs = [ pyasn1 ];
 
   meta = with stdenv.lib; {