Software keyloggers like the hypothetical "Shadow Keylogger" function by hooking into the operating system’s keyboard input stream.
The tool is designed to be completely hidden from the user, running as a background process that does not show up in the taskbar.
Traditional software requires installation. It writes entries to the Windows Registry, places files in the System32 folder, and creates uninstallation logs. This leaves a significant footprint—a digital trail that a savvy user can easily detect.