Definition - What does Keystroke Logger mean?
A keystroke logger is a device or program that allows the user to monitor what another user types into a device. In some cases, a keystroke logger is hardware that attaches to the keyboard or another part of a hardware system. In other cases, it is a program that is considered a type of spyware that can be slipped into a system and used in various ways, many of which are illegal.
A keystroke logger may also be called a keylogger.
Techopedia explains Keystroke Logger
In terms of the makeup of a keystroke logger spyware program, its most basic elements often include a dynamic link library (DLL), and an executable that runs the file. As the keystroke logger represents a somewhat common type of spyware or malware, there is a focus on how to identify, isolate and disarm these types of monitoring programs. Some users rely on utilities like tcpview to catch keystroke loggers, while others purchase anti-malware and anti-spyware programs that specialize in identifying these threats.