A keylogger is a type of software or hardware that records the keystrokes made on a computer or mobile device. This tool can capture everything typed, including passwords, messages, and other sensitive information. Keyloggers are often used for legitimate purposes, such as monitoring employee activity or parental control, but they can also be misused by cybercriminals to steal personal data. Keyloggers can be installed through malicious software or physical devices connected to a computer. They operate silently in the background, making it difficult for users to detect their presence. Protecting against keyloggers involves using antivirus software, keeping systems updated, and being cautious about downloading unknown applications.