I'm working on an oauth implementation based on http://bitoftech.net/2014/06/01/token-based-authentication-asp-net-web-api-2-owin-asp-net-identity/ by Taiseer Joudeh and want to add Microsoft Live support.
For Google and Facebook, the VerifyExternalAccessToken is in charge of checking the validity of the obtained token as described here https://developers.google.com/accounts/docs/OAuth2UserAgent#validatetoken
I may have missed a trivial info, but I can not find any Live equivalent for this validation...