Security Assertion Markup Language (SAML) is an XML standard that allows secure web domains communication of identities and organization. SAML is a framework for exchanging user authentication and authorization data. Using SAML, a service provider can contact a separate identity provider to authenticate users who are trying to access secure content.

The SAML specification defines three roles:

• The principal (typically an user)
• Identity Provider-

  Identity Provider creates, maintains and manages identity information and provides authentication to other service providers. It issues an authentication assertion in SAML SSO. The Identity Provider can functions as an authentication and an attribute authority by including attribute assertion in the response.

• Service Provider-

  Service Provider act as a relying party in SAML SSO which receives and accepts authentication and authorization(assertion) from identity provider. Service Provider provides services to principals or other system entities.

The most use case addressed by SAML is web browser SSO. SAML SSO works by transferring a users identity from one place(identity provider) to another(service provider) by exchanging the digitally signed XML documents. Let's assume the user is in the SSO environment and act as an identity provider where he wants to log in to a remote application(the service provider).

• The user loads the application by clicking on the link to application or similar.
• The application identifies the user origin either by application subdomain or user IP address and sends an authentication request by sending the user back to the identity provider for authentication.
• The user either has been registered with the identity provider or established new logging with the identity provider.
• The identity provider post an authentication response in the form of a base64 encoded XML document contains the user's attributes and signs it with X.509 certificate to the service provider(application).
• The service provider(which already knows the identity provider) retrieves the authentication response and validates it using the certificate signature.
• And the user relation established.

The Benefits of integrating SSO with SAML are:

• Reduce Password Loss:

  SAML SSO will eliminate password issues such as reset and recovery, which will reduce the time to recover old passwords.

• Reduced costs for the service provider:

  With SAML you don't have to maintain an account for multiple services. The identity provider will take burden for authentication and authorization.

• User experience:

  Without any authentication, a user can access multiple service provider by signing in just once which allows a faster and better experience at each service provider.

• Standardization:

  SAML is a standard format which allows interoperating with any system independent of implementation.It takes away the common issues associated with vendor and platform-specific approaches.

• Loose Coupling of Directories:

  SAML does not require maintaining and synchronized user information between directories.