Final answer:
The Security ID does not uniquely identify a user across all machines on the network; hence, the statement is false.
Step-by-step explanation:
The statement is False. The Security ID does not identify a user uniquely across all of the machines on the network. Instead, it is the combination of the username and password that serves as the unique identifier for a user. The Security ID, also known as the SID, is a unique identifier assigned to each user or group in a Windows domain-based network.
For example, if a user has the same username and password on multiple machines within the network, they would still have the same Security ID assigned to them on each machine. However, if they have a different username or password, a separate Security ID would be assigned for that combination on each machine.