PyCA cryptography 1.5.3 has been released to PyPI. cryptography is a package which provides cryptographic recipes and primitives to Python developers. Our goal is for it to be your "cryptographic standard library". We support Python 2.6-2.7, Python 3.3+, and PyPy. Changelog: SECURITY ISSUE: Fixed a bug where HKDF would return an empty byte-string if used with a length less than algorithm.digest_size. Credit to Markus Döring for reporting the issue. -Paul Kehrer (reaperhulk)