How to compare cb login user with user from outside

We need to validate users from outside in the Joomla site. How can we compare the user credentials.
What encryption does cb register do while creating users.

mbongio wrote: We need to validate users from outside in the Joomla site. How can we compare the user credentials.
What encryption does cb register do while creating users.

CB does not do anything different than Joomla.
In fact it uses Joomla functions to authenticate.

You would need to code a Joomla plugin to do this.
I think Joomla has some built-in authentication plugins you or your developers can study.
See Joomla plugins - Authentication Gmail, Authentiaction LDAP

Not much more I can offer on this Joomla related subject.

We tried using the authenticate plugin functions of Joomla and validate user credentials.
However we need to login the user to the site.
We tried using Curl Login method and we are getting error
Session expired or cookies are not enabled in your browser. Please press "reload page" in your browser, and enable cookies in your browser. Please refresh/reload page before filling-in.

Also we found when posting login data that the login form has hidden field cbsecuritym3 which is generated whenever we call the login page. Is this used the cb_login module to login user to the site.

We have a Joomla site and an eDirectory site. Users can login to eDirectory site using Joomla credentials. So from that site when they access the Joomla community site, they need to be looged in to the site. They should not need to login again to access the Joomla community site.

You need to write an authentication plugin to fit your needs. You can not login to Joomla/CB for a user that does not exist. The way these authentication plugins work is they valid the credentials then create a basic user on the site to allow login.

There's no functionality in Joomla to login externally. You would need a RESTful API to do that. A session needs to be created and a cookie needs to be generated to link the session to the browser. Without that they will never appear to be logged in.

CB Auto Actions maybe able to do this by creating a login action and calling its direct URL to trigger the login, but I've no idea if that'll truly work to generate the cookie and session properly for your usecase.

The user will be already registered in Joomla database. However in the scenario when they try to access Joomla community from another site they should not be asked to login again. They are already logging to the eDirectory site with the login details of Joomla. eDirectory through rest services sends us the info which we are able to validate. User is provided access to eDirectory and he may browse the page. Now if he clicks on the link which leads to Community site where he should not be asked to login again but shown as logged in.

This really is more of a question for Joomla and not CB. See my above reply for possible usage with CB, but beyond that you need something that generates the Joomla session and the cookie associated with that session. Either way you will likely need to custom code something to do this.