Authentication integration

Purpose

The OpenHatch website is comprised of a few pieces. There's the OpenHatch codebase in Django, but there's also this wiki and we are choosing a forum. I'd like logins to be integrated.

Strategy

Only applications in *.openhatch.org can receive user data. HMAC-SHA1 is used to verify the authenticity of the data that is passed through. Th

When (e.g.) the wiki wants to get the OpenHatch username and email address corresponding to the current session, it

Application: redirect

If the wiki detects an OpenHatch session cookie, it redirects the user to http://openhatch.org/+create_user_data_cookie?redirect_to=http://openhatch.org/wiki/handle_login.php

Django code: create_user_data cookies

The OpenHatch site creates some cookies. All cookies contain text. We encode it as UTF-8 and then wrap that in base64.

The "message" that we HMAC is the final, base64-encoded data.

• user_data__email_address: This contains the user's email address.
• user_data__email_address__hmac: This contains a HMAC-SHA1 to verify the authenticity of the email address.
• user_data__username: This contains the user's username.
• user_data__username__hmac: This contains a HMAC-SHA1 of the username.

Application: Read cookie data, then delete cookies

Now it's time for the application (e.g., the wiki) to read the user data and log the user in.

It should delete the user_data__* cookies that it read, to avoid keeping clutter in the user's browser.

That's up to the application. It MUST verify the user_data__* using HMAC-SHA1 before trusting it, as users can tamper with this data.

The application should make its own "logged in" status expire at the end of the session.