Use a version check when counting bit_length
diff --git a/cryptography/hazmat/primitives/asymmetric/rsa.py b/cryptography/hazmat/primitives/asymmetric/rsa.py
index c5fecbc..3dd88e9 100644
--- a/cryptography/hazmat/primitives/asymmetric/rsa.py
+++ b/cryptography/hazmat/primitives/asymmetric/rsa.py
@@ -13,6 +13,8 @@
from __future__ import absolute_import, division, print_function
+import sys
+
import six
from cryptography import utils
@@ -20,9 +22,9 @@
def _bit_length(x):
- try:
+ if sys.version_info >= (2, 7):
return x.bit_length()
- except AttributeError:
+ else:
return len(bin(x)) - (2 + (x <= 0))