I am having an REST web service (for user authentication) and with the help of that I have to integrate sso for applications (which could be hosted on DIFFERENT DOMAIN).
I googled the stuff regarding SSO and found some solution in the form of cas & josso.
I also studied a bit about SAML and OAUTH2 but didn't found a good example for it, Could someone please point me in the right direction how to implement SSO?
NOTE : The Implementation must make the use of web service to authenticate the user.
You will have to make your Web Service receive the authentication token form a Security Token Service (STS) that is trusted by both domains for which you want to provide SSO. A common standard to broker authentication tokens is SAML; as far as I know, also josso uses SAML for the exchange of authentication information.
If you are looking for some code, I recommend the Axis2 samples, which contain an example for SSO authentication via a STS.