I need a Python library that supports PEM files and both RSA signing and DES3 encryption. pycrypto doesn't seem to support PEM, and its mechanism for loading existing keys is undocumented and cryptic. m2crypto doesn't seem to support DES/DES3, oddly. I've been running an openssl subprocess, but I'd rather have something built in and preferably fast. Does this exist? (Failing that, I hesitate to ask, but are there high-level enough C apis available for this that I could write a special-purpose extension without killing myself/introducing vulns?)