What role does Zscaler serve in SAML authentication?

Zscaler primarily acts as a Service Provider (SP) in SAML authentication. In a SAML setup, the Service Provider is the system that receives and processes authentication requests from users, typically seeking access to an application or service. When a user attempts to access a resource protected by Zscaler, the SP (Zscaler) redirects the user to the Identity Provider (IdP) for authentication.

This process involves Zscaler working together with an Identity Provider, which is responsible for validating the user's credentials and returning a SAML assertion back to the Service Provider upon successful authentication. Zscaler's role as an SP means that it trusts the assertions made by the IdP, thus allowing users to access protected applications or resources without needing to re-enter their credentials after they've logged in through the IdP.

The other roles mentioned in the choices, such as Identity Provider, Authentication server, and Assertion issuer, do not accurately represent Zscaler's function in this context. These roles are designated to different components in the SAML framework, with the IdP typically handling user authentication and assertion issuance.