I have been trying for many days to create a custom authentication plugin using OpenID for Joomla 2.5. I first used this extension: http://extensions.joomla.org/extensions/access-a-security/site-access/authentication-cloud-based/5366. It has a CAS plugin, but no OpenID plugin. I tried to use the CAS login plugin format for OpenID but my level of joomla/php/openid/cas knowledge is insufficient and it does not work.
I have also tried to use some available libraries such as lightopenid. It works on a custom-built website based on php, but I have tried to apply it to Joomla 2.5 with no success.
The next alternative is to use Janrain's OpenID (which was used in Joomla 1.5 actually). I am in the process of adapting the code from Joomla 1.5 to 2.5.
Has anyone been able to successfully develop a custom authentication plugin using OpenID for Joomla 2.5? Which of the above methods would you recommend? I do not want to use 3rd party apps such as Social Login and Social Share (which currently works), but to have it in-built into the normal Joomla login module.
Hope to be able to receive some help in developing such a plugin.