SSO support with DUO MFA

[Rich Graves]

The Multi Context Broker and its Duo plugin handle the step-up case. Unlike DuoUserPassword, they are also available as easily (relative to Shib) installable binaries, though they still require extensive configuration.

I'm writing a SANS Gold paper on the Shib+MCB+Duo combination and plan to distribute a ready-to-run CentOS 6 VM to go with it. It's going to take me at least another month to finish, but if RHEL6/CentOS6 is an acceptable platform for you and you are interested in a very early preview, let me know.