Steam openid plugin

I am trying to work out how to integrate into wordpress a way of allowing users to login using there steam id, steam runs it via openid as far as I can tell. Would it be possible to mod an existing openid plugin, or will it be completely different?

steam openid info is here:

https://steamcommunity.com/dev/

and more here

https://developer.valvesoftware.com/wiki/Steam_Web_API

Any help or info greatly appreciated.