Perhaps this is a sensible way to declare a dependency on post-0.6.1 master? Perhaps not, I'm not sure.
This might be nonsense.
diff --git a/setup.py b/setup.py
index 65a1b52..8d9d12a 100755
--- a/setup.py
+++ b/setup.py
@@ -34,7 +34,7 @@
maintainer_email = 'exarkun@twistedmatrix.com',
url = 'https://github.com/pyca/pyopenssl',
license = 'APL2',
- install_requires=["cryptography>=0.7", "six>=1.5.2"],
+ install_requires=["cryptography>=0.7.dev0", "six>=1.5.2"],
long_description = """\
High-level wrapper around a subset of the OpenSSL library, includes
* SSL.Connection objects, wrapping the methods of Python's portable