Using XML-DSig (XML Digital Signature) and OpenSSL from Python scripts is not straightforward, but there are solutions. Here are a few links to useful libraries and articles.

XML Signature (XML-DSig):

• I have not found an easy to use Python module to create and verify XML signatures, so I decided to create my own on top of PyXMLSec: pyxmldsig.
• PyXMLSec (Python bindings for XMLSec): http://pyxmlsec.labs.libre-entreprise.org/
  • Binary installer for Windows: http://returnbooleantrue.blogspot.com/2009/04/pyxmlsec-windows-binary.html
  • XMLSec library: http://www.aleksey.com/xmlsec/
• IdentityMeme.org, "XMLdsig implementations for scripting languages": http://identitymeme.org/archives/2006/12/20/xmldsig-implementations-for-...
• Verisign Labs, "XMLSIG for dynamic languages": http://xmlsig.sourceforge.net/ - get code using SVN repository from http://sourceforge.net/projects/xmlsig/
  

OpenSSL:

• pyopenssl: http://pyopenssl.sourceforge.net/
• eGenix.com pyOpenSSL Distribution: http://www.egenix.com/products/python/pyOpenSSL/
• pyOpenSSL: https://launchpad.net/pyopenssl/
• M2Crypto: http://chandlerproject.org/bin/view/Projects/MeTooCrypto
  • useful tutorials: http://chandlerproject.org/Projects/MeTooCrypto#Documentation

Other crypto libraries:

• PyCrypto: http://www.amk.ca/python/code/crypto.html
• ezPyCrypto: http://www.freenet.org.nz/ezPyCrypto/
• yawPyCrypto: http://sourceforge.net/projects/yawpycrypto
• pycryptopp: http://pypi.python.org/pypi/pycryptopp
• asym: http://pypi.python.org/pypi/asym

Of course if you know other useful libraries and documentation, please leave a comment below or e-mail me at decalage(à)laposte.net.