Require cryptography >= 1.4, replace deprecated function

The signer/verifier interfaces are deprecated in cryptography==2.0. The
alternative sign/verify interfaces were added in cryptography==1.4.

1 files changed, 1 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index 7124ded..e8c54cf 100755
--- a/setup.py
+++ b/setup.py
@@ -70,7 +70,7 @@ setup(
     tests_require=tests_require,
     extras_require=dict(
         test=tests_require,
-        crypto=['cryptography >= 1.0'],
+        crypto=['cryptography >= 1.4'],
         flake8=[
             'flake8',
             'flake8-import-order',