Given this article about the NSA's ANT Catalog, which hacking tools can be used to monitor a target's key strokes?
SURLYSPAWN, KEYSWEEPER, and TINYALAMO are monitoring technologies that can be used to monitor target's key strokes.
SURLYSPAWN is a keystroke monitor technology that can be used on remote computers that are not internet connected.
KEYSWEEPER is a keylogger in form of a USB wall charger, that wirelessly and passively sniffs, decrypts, logs and reports back (over GSM).
TINYALAMO is software that targets BLE (Bluetooth Low Energy) and allows keystroke surveillance (keylogger) and injection.