Yes, you can use any alpha-numeric string as an auth-key (and make sure to keep it secure). You can also use a Facebook Connect, Google+, Twitter token or any home-grown solution as well for the auth-key.
Can a UUID serve as an auth key?
Yes, you can use any alpha-numeric string as an auth-key (and make sure to keep it secure). You can also use a Facebook Connect, Google+, Twitter token or any home-grown solution as well for the auth-key.