Final answer:
Live Terminal uses the SSH protocol to ensure a secure and encrypted connection with XDR agents.
Step-by-step explanation:
The protocol used by Live Terminal to connect to XDR agents is SSH (Secure Shell). SSH is a network protocol that allows for secure remote login and other secure network services over an insecure network. It provides a secure channel over an unsecured network in a client-server architecture, connecting an SSH client application with an SSH server. Its use in establishing a secure connection with XDR agents ensures that all communications are encrypted and secure from unauthorized access or eavesdropping.