Now the calendar creation application can access and import the user's photos to create a calendar. If the access token is valid, the resource server returns the requested resources to the calendar creation application (client).The client can now request the protected resources from the resource server - Google Drive in this example - by presenting the access token for authentication.If the client identity is authenticated and the authorization grant is valid, the authorization server or authentication provider - Google's Authorization Server in this instance - will issue an access token to the client.The client then requests an access token from the authorization server by presenting the authorization grant returned from the authorize endpoint along with authentication of its own identity to the token endpoint.The OAuth 2.0 protocol defines four types of grants: Authorization Code, Client Credentials, Device Code and Refresh Token. The resource owner authenticates and authorizes the resource access request from the application, and the authorize endpoint returns an authorization grant to the client.The calendar creation application (the client) requests authorization to access protected resources, in this case image files, owned by the user (resource owner) by directing the user to the authorize endpoint.In the example below, an online calendar creation application needs to be able to access a user's photos stored on their Google Drive: The authorization flow in a typical OAuth 2.0 implementation is a six-step process. Updated features include a new authorization code flow to accommodate mobile applications, simplified signatures and short-lived tokens with long-lived authorizations. However, it is a completely new protocol, and is not backward compatible with OAuth 1.0. Like the original OAuth, OAuth 2.0 provides users with the ability to grant third-party application access to web resources without sharing a password. In 2010, the IETF OAuth Working Group published the first draft of the OAuth 2.0 protocol. OAuth 1.0 was first released in 2007 as an authorization method for the Twitter application program interface ( API). The process for obtaining the token is called an authorization flow. It acts as an intermediary on behalf of the end user, providing the third-party service with an access token that authorizes specific account information to be shared. OAuth, which is pronounced "oh-auth," enables an end user's account information to be used by third-party services, such as Facebook and Google, without exposing the user's account credentials to the third party. Without a canary, the request will come back with an HTTP 500.OAuth (Open Authorization) is an open standard authorization framework for token-based authorization on the internet. Each request to an /ecp page is required to have a ticket known as the “ECP canary”. There is one additional hurdle to clear before we can successfully issue an unauthenticated request, but it turns out to be a minor one. The net result is that requests can sail through, without being subjected to authentication on either the front or back end. Meanwhile, the back end is completely unaware that it needs to authenticate some incoming requests based upon the SecurityToken cookie, since the DelegatedAuthModule is not loaded in installations that have not been configured to use the special delegated authentication feature. In summary, when the front end sees the SecurityToken cookie, it knows that the back end alone is responsible for authenticating this request. In .SelectHandlerForUnauthenticatedRequest:Īs you can see, in a default configuration of the product, a element appears, so that the module DelegatedAuthModule will not be loaded at all for the back-end ECP site. These requests that are to be authenticated using back-end logic are identified by the presence of a SecurityToken cookie: Instead, the front end passes requests directly to the back end, relying on the back end to determine whether the request is properly authenticated. In such deployments, the front end is not able to perform authentication decisions on its own. In particular, Exchange supports a feature called “Delegated Authentication” supporting cross-forest topologies. It then collects the responses from the back end and forwards them to the client.Įxchange is a highly complex product, though, and this can lead to some wrinkles in the usual flow. For all post-authentication requests, the front end’s main role is to repackage the requests and proxy them to corresponding endpoints on the Exchange Back End site. To allow access that requires forms authentication, the front end serves pages such as /owa/auth/logon.aspx. The front-end website is mostly just a proxy to the back end.
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