First task I am going to do for my GSoC project is to have login authentication mechanism for HyperKitty users. I have had discussion with few mailman developers about it. I am planning to wrap up social_auth into mm_ui_auth django application. Both postorius and HyperKitty can use this app for authenticating users.
Feel free to suggest if you have any ideas about how login should work in HyperKitty.