Which of the following best describes the use of PAC in EAP-FAST Phase 1?

In EAP-FAST (Extensible Authentication Protocol-Fast Authentication Setup), Phase 1 is focused on establishing a secure channel between the client and the authentication server. This process begins with the negotiation of the Protected Access Credential (PAC), which is a secret value that facilitates the establishment of a secure tunnel. Once the PAC is in place, it helps ensure that the data transferred during the authentication process is protected from potential eavesdropping or tampering, making it a key component in maintaining confidentiality.

This secure channel is crucial for the following phases of EAP-FAST, as it ensures that subsequent messages, which involve user authentication and other sensitive data, can be transmitted safely without risk from external threats. This foundational step is vital to the overall integrity of the authentication process carried out through EAP-FAST.

Understanding the role of PAC in Phase 1 helps clarify why it is essential to establish this secure channel before moving on to other aspects of the authentication, such as credential verification or session key encryption.