The current crowd authorization module only allows http connections to the crowd server for authorization. This means that crowd servers hosted behind a proxy to server https or direct using https cannot be used by the current auth_crowd.py plugin.
What I expected: To be able to connect to crowd using https.
What I got: There's no way to configure the crowd authorization to use https.
It appears the back-end code is written for it. There just isn't an interface option.