I have my blog running on wordpress and I am building another web app that has django as its backend.
My authentication is being done by wordpress. The only thing that needs to be done is : if the user is logged in on the blog, welcome her to the django based app, else revert back to the wordpress to request signin.
I think you should look at the django-wordpress-auth library which allows to check wordpress login status and roles : https://github.com/dellis23/django-wordpress-auth