Role of the identity provider

Modern authentication is an umbrella term for authentication and authorization methods between a client, such as your laptop or phone, and a server, like a website or application. At the center of modern authentication is the role of the identity provider. An identity provider creates, maintains, and manages identity information while offering authentication, authorization, and auditing services.

With modern authentication, all services, including all authentication services, are supplied by a central identity provider. Information that's used to authenticate the user with the server is stored and managed centrally by the identity provider.

With a central identity provider, organizations can establish authentication and authorization policies, monitor user behavior, identify suspicious activities, and reduce malicious attacks.

The client communicates with the identity provider by giving an identity that can be authenticated. When the identity (which can be a user or an application) has been verified, the identity provider issues a security token that the client sends to the server.

The server validates the security token through its trust relationship with the identity provider. By using the security token and the information that's contained within it, the user or application accesses the required resources on the server. In this scenario, the token and the information it contains is stored and managed by the identity provider. The centralized identity provider is supplying the authentication service.

Microsoft Azure Active Directory is an example of a cloud-based identity provider. Other examples include Twitter, Google, Amazon, LinkedIn, and GitHub.

Single sign-on

Another fundamental capability of an identity provider and “modern authentication” is the support for single sign-on (SSO). With SSO, the user logs in once and that credential is used to access multiple applications or resources. When you set up SSO between multiple identity providers, it's called federation.