Or switch to alternate keyboard layouts that have dissimilar key distances & locations. Using Dvorak/Colemak etc would throw this method off unless it managed

Or switch to alternate keyboard layouts that have dissimilar key distances & locations. Using Dvorak/Colemak etc would throw this method off unless it managed to retrain for the particular differences due to layouts. Maybe a random layout generator that would mask this effect and only cost typing speed for the extra defense?