The primary function of a keylogger in cybersecurity is to secretly record keystrokes made by a user on their device. This can include capturing sensitive information such as passwords, credit card details, and personal messages. While keyloggers can be used maliciously by attackers to gain unauthorized access to sensitive data, they can also serve legitimate purposes, such as monitoring employee activity or conducting security assessments. Awareness of keyloggers is essential for educating users about potential security threats and employing countermeasures to protect against data breaches.