I recently posted a link to pycrypto in the blogmarks - I've now used it in the Toolserver Framework for Python to add encrypted RPCs and RSA authentication. I have to say, I'm really enthusiastic about this library - you can achieve results very simply and quickly, the interfaces of the various algorithms are very sensibly designed, and it's a good collection of algorithms - including often neglected areas like proper random number generation (including access to operating system mechanisms for this purpose, on Linux, OS X, and even Windows!). So if you're planning a project with Python and cryptography, definitely check out this library. It's so simple to use that it's even suitable as a standard library for small use cases - for example, for encrypting passwords or similar purposes. Somehow remarkable, I'm now using the second project maintained by Andrew Kuchling: in the Toolserver Framework for Python, the Medusa server is included as the web server - a fast and compact web server written in Python with many interesting extension options. The original article is here.