3rd party Authentication
 

We have a central authentication service (CAS) which we want to integrate vBulletin with, this CAS will be used by vBulletin and other applications as well, in another words, CAS will become the primary user base. So we need to integrate with this CAS in exactly the following 3 operations:

1. Login (to verify users)
2. Registration (to tell it about new users)
3. Changing of passwords or e-mails (to allow users to change their passwords or e-mails)

I'm not looking for coding help, but guidance concerning the internals of vBulletin (3.7.6) :)

Data wise, we want to offload only the e-mail, username and password to CAS. Everything else remains in vBulletin.

Do you have any recommendations you can give us in this regard? To put it in terms of questions, we would like to know:

1. Which integration points we should plug into for each of the 3 operations. The vBulletin code base is pretty huge and we are concerned that we might not fully grasp the big picture and miss a thing or two which would give us headaches later.
2. If we can, and you recommend, using certain hooks to achieve this integration, as an alternate to modifying files directly. (login.php, ..etc.)
3. If there are certain mods/hacks which do something similar (regardless of the backend they integrate with) and you would recommend them as a good example of integration which is done right.
4. Tips for avoiding shooting ourselves in the foot :)

Many thanks in advance.

Kind Regards,