In a RADIUS access-request packet, which field is encrypted?

The correct answer is password. In a RADIUS access-request packet, only the password field is encrypted. This is a critical security feature, ensuring that user credentials are not transmitted in plain text over the network, which could be intercepted. The encryption uses a shared secret key between the RADIUS client (e.g., a network access server) and the RADIUS server. The other options are incorrect because: authorized services: This field is typically not encrypted and contains information about the services the user is authorized to access, which is determined by the server after authentication. authenticator: The authenticator field is used for integrity checking and challenge-response mechanisms, but its content itself is not encrypted in the same way the password is. It helps prevent replay attacks and verifies the integrity of the packet. username: The username is transmitted in plain text to allow the RADIUS server to identify the user and retrieve their credentials for comparison with the provided (encrypted) password.