I notice that there is an *oAuth* endpoint for the stackexchange API: https://api.stackexchange.com/docs/authentication

The [*OpenID* implementation used by StackExchange is open sourced][1] at https://code.google.com/p/stackid/ 

**Is there an open source implementation of the oAuth2 provider capabilities used by stackexchange API?**
If not, any information on what [(C#?) implementation][2] the stackexchange network uses?


  [1]: https://code.google.com/p/stackid/
  [2]: http://stackoverflow.com/questions/3997172/oauth-2-0-service-provider-net-libraries/