Suggestion on how to enable access to the private endpoints without forcing the user to log into a third party app with PSN, XBL logins

This could be solved much in the same way that various music services do. 1. The user first logs into the bungie site using PSN, xbox, whatever. 2. The user goes to a page (settings/preferences) and copies a generated string that is unique for that user. 3. Paste this key into the third party app. Boom, autenticated! Allow the user to generate a new key with a button press in the Bungie site (when logged in), this will at the same invalidate the existing key. This would of course require a change in how the api works and a db on bungies side to track these unique keys.