1 files changed, 1 insertions, 1 deletions
diff --git a/setup.py b/setup.py
index 884476d1..63fde7bb 100644
--- a/setup.py
+++ b/setup.py
@@ -36,7 +36,7 @@ import sys
 try:
     from setuptools import setup
     kw = {
-        'install_requires': 'pycrypto >= 2.1',
+        'install_requires': 'pycrypto >= 2.1, < 2.4',
     }
 except ImportError:
     from distutils.core import setup