What behavior does 'Idle' authentication timeout signify?

The 'Idle' authentication timeout specifically refers to the termination of a session based on the duration of user inactivity. When a user is logged in but does not perform any actions for a specified period, the system recognizes this inactivity and automatically logs the user out. This mechanism is essential in enhancing security by ensuring that sessions do not remain open indefinitely, which could allow unauthorized users to access the system if the legitimate user steps away.

In contrast, the other options describe different behaviors that are not applicable to 'Idle' authentication. The second choice relates to a timeout that occurs after a fixed duration post-login, which does not take into account user activity, while the third option refers to timeouts based on new session inactivity rather than user inactivity during an active session. The last option suggests that sessions never time out, which contradicts the fundamental purpose of implementing timeouts for security and operational efficiency.