Azure AD AuthN stuff

azuread-authn.cs

string resourceId = "<resource id>"; 
// Can be:
//    For SharePoint (CSOM), tenant Url: https://tenant.sharepoint.com
//    For Azure AD Graph: https://graph.windows.net
//    For Office 365 Discovery: https://api.office.com/discovery/
//    For Exchange Online: https://outlook.office365.com/

string secret = "<App client secret>"; // a generated guid
Uri redirectUri = new Uri("<App redirect Uri>"); // for instance app://my-app

AuthenticationContext context = new AuthenticationContext("https://login.windows.net/common");
AuthenticationResult result = context.AcquireToken(resourceId, secret, redirectUri);