Identity federation
Identity federation allows you to use your identity with a third party. Many organizations will use services in the cloud such as software as a service. This allows the user to use SSO in their own enterprise and when accessing these third-party applications. Users only need to remember one identity. Typically, a token will be generated by an identity federation service and passed securely to the third party. Microsoft provides a service called Active Directory Federation Services (ADFS), which allows an authenticated enterprise user to use their credentials on a third-party site. They support many of the standard protocols in use out there including Security Assertion Markup Language (SAML).
Transitive trust
Transitive trust can be very useful within complex enterprise environments. When using directory services, we can create security boundaries referred to as domains or Kerberos realms. It is common to create these boundaries to separate account management...