Hello Manuel,
Employees are accessing many different resources either in the intranet or—due to increasing cloud business—across the Internet to do their daily jobs. Therefore companies need to maintain a complex
but secure working environment while ensuring users remain productive. Single sign-on (SSO) is ideal for achieving both objectives.
Web-based SSO works across the Internet. It allows users with Web browsers to securely and easily
access multiple Web applications while only logging in once, even though the applications are most likely managed by different organizations. The key to implementing Web-based SSO is the Security Assertion Markup Language (SAML) standard protocol to share federated identities securely across disparate networks and applications.
In order for identity federation to work, a few prerequisites must be met. First, a user must be authenticated by an organization. The organization that "owns" the user’s identity is known as the identity provider (IdP). But identity federation also assumes that another organization owns the data and applications that the IdP user needs to access via Web SSO. These organizations are known as service providers (SP).
Also as Suman mentioned you can check the above links on how to achieve this.
Thanks & Regards,
--Sathya Swaroop