Microsoft.SharePoint.IdentityModel.OAuth2 namespace

SharePoint 2013

  Class Description
Public class OAuth2BearerCredentials Provides the base implementation of OAuth 2.0 bearer token credentials used for Web client authentication.
Public class OAuth2EndpointIdentity
Public class SPOAuth2BearerCredentials Provides credentials for authentication with a service that supports OAuth 2.0 bearer token authentication.
Public class SPOAuth2ErrorResponseException
Public class SPOAuthNativeClientAuthenticationService

  Interface Description
Public interface IIdentityClaimsResolver