What is the primary function of a keylogger?

The primary function of a keylogger is to record keystrokes made by a user to capture sensitive information. Keyloggers are often utilized by malicious actors to gather personal data such as passwords, credit card numbers, and other confidential information without the user's knowledge. By logging every key press, the keylogger can provide a comprehensive record of user activity, making it a potent tool for those looking to exploit weak security practices.

The other options refer to different types of security tools or malware. Blocking unauthorized access is a function associated with firewalls and security software, while encryption tools specifically safeguard files by scrambling their contents. Additionally, scanning networks for vulnerabilities is the role of network scanning tools or vulnerability assessment software, which are geared towards identifying security flaws in systems rather than monitoring user inputs. Each of these tools serves important functions in the cybersecurity landscape, but they do not fulfill the specific role of a keylogger.