In some computer security systems, a Ticket Granting Ticket (TGT) is a small, encrypted identification file with a limited validity period. After authentication, this file is granted to a user for data traffic protection by the key distribution center (KDC) subsystem of authentication services like Kerberos. The TGT file contains the session key, its expiration date, and the user's IP address, which protects the user from man-in-the-middle attacks.