that they can continue communicating in a secure manner. To verify that mutual authentication has occurred successfully, Burrows-Abadi-Needham logic (BAN logic) is a well regarded and widely accepted method to use, because it verifies that a message came from a trustworthy entity. BAN logic first assumes an entity is not to be trusted, and then will verify its legality. Defenses Mutual authentication supports zero trust networking because it can protect communications against adversarial attacks, notably: Man-in-the-middle attack Man-in-the-middle (MITM) attacks are when a third party wishes to eavesdrop or intercept a message, and sometimes alter the intended message for the recipient. The two parties openly receive messages without verifying the sender, so they do not realize an adversary has inserted themselves into the communication line. Mutual authentication can prevent MITM attacks because both the sender and recipient verify each other before sending them their message keys, so if one of the parties is not verified to be who they claim they are, the session will end. Replay attack A replay attack is similar to a MITM attack in which older messages are replayed out of context to fool the server. However, this does not work against schemes using mutual authentication because timestamps are a verification factor that are used in the protocols. If the change in time is greater than the maximum allowed time delay, the session will be aborted. Similarly, messages can include a randomly generated number to keep track of when a message was sent. Spoofing attack Spoofing attacks rely on using false data to pose as another user in order to gain access to a server or be identified as someone else. Mutual authentication can prevent spoofing attacks because the server will authenticate the user as well, and verify that they have the correct session key before allowing any further communication and access. Impersonation attacks When each party authenticates the other, they send each other a certificate that only the other party knows how to unscramble, verifying themselves as a trusted source. In this way, adversaries cannot use impersonation attacks because they do not have the correct certificate to act as if they are the other party. Mutual authentication also ensures information integrity because if the parties are verified to be the correct source, then the information received is reliable as well. mTLS By default the TLS protocol only proves the identity of the server to the