This usually refers to a piece of software installed on a computing device which records everything that is typed on the keyboard, including passwords and other credentials inputted into the device. The recorded data is then sent over the internet to be used by the attacker. Keyloggers were extensively used by the Zeus banking trojan to capture bank login credentials. A keylogger can also take the form of a hardware device. For example, a hardware keylogger can interface between a computer’s USB port and keyboard to record inputted data.